CVE-2026-98080

MEDIUMNVD 5.55.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 5.5 from GitHub Security Advisory published 2026-09-25. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2026-86910 (ENISA EUVD) · GHSA-m4cg-769c-m465 (GitHub Security Advisories)Source: ENISA EUVD

5.5EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 5.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

btrfs: do not force reloc root creation during qgroup_account_snapshot()

[BUG] When running btrfs/252 with quota enabled through MKFS_OPTIONS="-O quota", it has a high chance to trigger the following kernel warning and flips the fs RO:

BTRFS info (device dm-2): relocating block group 30408704 flags metadata|dup ------------[ cut here ]------------ WARNING: fs/btrfs/extent-tree.c:879 at lookup_inline_extent_backref+0x74b/0x960 [btrfs], CPU#4: btrfs/2173 CPU: 4 UID: 0 PID: 2173 Comm: btrfs Not tainted 7.2.0-rc6-custom+ #457 PREEMPT(full) 3adc6528fb66f7a55fe1095385818e742f200aab Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS unknown 02/02/2022 RIP: 0010:lookup_inline_extent_backref+0x74b/0x960 [btrfs] Call Trace: insert_inline_extent_backref+0x7c/0x160 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] __btrfs_inc_extent_ref+0xa9/0x270 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] __btrfs_run_delayed_refs+0x4af/0x11c0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] btrfs_run_delayed_refs+0x9d/0xf0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] create_pending_snapshot+0x39d/0xf00 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] create_pending_snapshots+0x9b/0xc0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] btrfs_commit_transaction+0x280/0xeb0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] prepare_to_relocate+0x147/0x200 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] relocate_block_group+0x6b/0x5e0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] btrfs_relocate_block_group+0x92c/0x2380 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] btrfs_relocate_chunk+0x3f/0x1a0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] btrfs_balance+0xa2c/0x19c0 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] btrfs_ioctl+0x2839/0x2d30 [btrfs 32f09462c54d9c922fca74a3e4866f4aa7737b72] __x64_sys_ioctl+0x416/0x9a0 do_syscall_64+0xe1/0x790 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ---[ end trace 0000000000000000 ]--- BTRFS info (device dm-2): leaf 4593991680 gen 233 total ptrs 175 free space 5953 owner 2 BTRFS info (device dm-2): refs 3 lock_owner 2173 current 2173 item 0 key (166772736 METADATA_ITEM 1) itemoff 16250 itemsize 33 extent refs 1 gen 222 flags 2 ref#0: tree block backref root 266 [ Skip the tree dump ] item 174 key (263225344 METADATA_ITEM 0) itemoff 10328 itemsize 33 extent refs 1 gen 162 flags 258 ref#0: tree block backref root 267 BTRFS error (device dm-2): extent item not found for insert, bytenr 179847168 num_bytes 16384 parent 4594335744 root_objectid 273 owner 0 offset 0 BTRFS error (device dm-2): failed to run delayed ref for logical 179847168 num_bytes 16384 type 182 action 1 ref_mod 1: -117

[CAUSE] The above error is showing that there is a tree reference to a metadata extent that is no longer there.

With "ref_verify" mount option (requires CONFIG_BTRFS_DEBUG), there is some extra debug output:

BTRFS error (device dm-2): dumping block entry [180961280 16384], num_refs 0, metadata 1, from disk 0 BTRFS error (device dm-2): root entry 256, num_refs 18446744073709551615 BTRFS error (device dm-2): root entry 273, num_refs 18446744073709551615 BTRFS error (device dm-2): Ref action 3, root 273, ref_root 273, parent 0, owner 0, offset 0, num_refs 1 btrfs_force_cow_block+0x129/0x7d0 [btrfs] btrfs_cow_block+0x10a/0x250 [btrfs] btrfs_search_slot+0x5eb/0xf40 [btrfs] btrfs_insert_empty_items+0x3a/0x70 [btrfs] insert_with_overflow+0x53/0x130 [btrfs] btrfs_insert_dir_item+0x125/0x290 [btrfs] btrfs_add_link+0xaa/0x410 [btrfs] btrfs_rename+0x5ea/0xcd0 [btrfs] btrfs_rename2+0x28/0x60 [btrfs] vfs_rename+0x5b2/0xe10 filename_renameat2+0x244/0x430 __x64_sys_rename+0x48/0x70 do_syscall_64+0xe1/0x790 entry_SYSCALL_64_after_hwframe+0x4b/0x53 ---truncated---

CVSS v3
5.5
EG Score
5.5MEDIUMmedium confidence
EG Risk
25
EG Risk 25/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity55% × 45%
Impact severity (EG Severity): CVSS 5.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.1%
EPSS %ILE
2nd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.

EG Severity
5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-24). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

September 25, 2026

Last Modified

October 19, 2026

Advisory Details (7)

Auto-updated Oct 6, 2026
Patch available.
Web page

btrfs: do not force reloc root creation during qgroup_account_snapshot() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/d0284d974be46a0a06068f930c84039d540ae8ed
Web page

btrfs: do not force reloc root creation during qgroup_account_snapshot() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/cacf35832292997018837e484283f95a9301ebf5
Web page

btrfs: do not force reloc root creation during qgroup_account_snapshot() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c4c78768d1a8ceb713693cc5524acbe984c31f3c
Web page

btrfs: do not force reloc root creation during qgroup_account_snapshot() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b5d5ab5a715001dd937c920ef8c5688fd4999ba1
Web page

btrfs: do not force reloc root creation during qgroup_account_snapshot() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7caaae233a55e167063f4cfa3385b1a04c8bbecb
Web page

btrfs: do not force reloc root creation during qgroup_account_snapshot() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/21bd77c132f18dc21c6fcdf417310d1adcf7448b
Web page

btrfs: do not force reloc root creation during qgroup_account_snapshot() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/203cbfb4fba590bd9b08bd36fa6d05b5d28923bf

Vendor Advisories for CVE-2026-98080(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 3 ecosystems)
Debian:12(2)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 7.2~rc7-1~exp1 (360 versions)
  • every version on: no fix on record
—
linux-6.126.12.100-1~deb12u1, 6.12.101-1~deb12u1, 6.12.107-1~deb12u1
  • every version up to 6.12.111-1~deb12u1: fixed in 6.12.111-1~deb12u1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 6.12.96-1 (35 versions)
  • every version up to 6.12.111-1: fixed in 6.12.111-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.2~rc7-1~exp1 (180 versions)
  • every version up to 7.2.7-1: fixed in 7.2.7-1
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 6× in last 7d / 60× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. 1 repeat row among the latest 82 is merged into the row it repeats.

  1. 2026-11-01 16:36 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  3. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  4. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  5. 2026-10-27 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  6. 2026-10-26 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  7. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  8. 2026-10-25 13:47 UTCEG score recompute
  9. 2026-10-25 12:34 UTCEG score recompute
  10. 2026-10-25 12:34 UTCVendor advisory
  11. 2026-10-25 12:34 UTCGHSA enrichmentGHSA-m4cg-769c-m465 · GitHub CVSS 5.5
  12. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  13. 2026-10-23 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  14. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  15. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  16. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  17. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  18. 2026-10-19 10:30 UTCVendor advisory
  19. 2026-10-19 10:29 UTCGHSA enrichmentGHSA-m4cg-769c-m465 · GitHub CVSS 5.5
  20. 2026-10-19 09:46 UTCEG score recompute
  21. 2026-10-19 09:46 UTCVendor advisory
  22. 2026-10-19 09:46 UTCGHSA enrichmentGHSA-m4cg-769c-m465 · GitHub CVSS 5.5
  23. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  24. 2026-10-18 02:56 UTCEG score recompute
  25. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
Show 56 more
  1. 2026-10-16 16:45 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  2. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  3. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  4. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  5. 2026-10-12 14:39 UTCEG score recompute
  6. 2026-10-11 19:10 UTCEG score recompute
  7. 2026-10-11 18:20 UTCVendor advisory
  8. 2026-10-11 18:20 UTCGHSA enrichmentGHSA-m4cg-769c-m465 · GitHub CVSS 5.5
  9. 2026-10-11 16:25 UTCEG score recompute
  10. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  11. 2026-10-11 13:37 UTCEG score recompute
  12. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  13. 2026-10-10 18:06 UTCEG score recompute
  14. 2026-10-10 18:06 UTCGHSA enrichmentGHSA-m4cg-769c-m465 · GitHub CVSS 5.5
  15. 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  16. 2026-10-09 18:00 UTCVendor advisory
  17. 2026-10-09 18:00 UTCGHSA enrichmentGHSA-m4cg-769c-m465 · GitHub CVSS 5.5
  18. 2026-10-08 17:54 UTCEG score recompute
  19. 2026-10-08 17:54 UTCVendor advisory
  20. 2026-10-08 17:54 UTCGHSA enrichmentGHSA-m4cg-769c-m465 · GitHub CVSS 5.5
  21. 2026-10-08 17:14 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  22. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  23. 2026-10-07 17:40 UTCEG score recompute
  24. 2026-10-07 17:40 UTCVendor advisory
  25. 2026-10-07 17:40 UTCGHSA enrichmentGHSA-m4cg-769c-m465 · GitHub CVSS 5.5
  26. 2026-10-06 17:08 UTCEG score recomputeFirst assessed: 5.5 MEDIUM
  27. 2026-10-06 17:08 UTCVendor advisory
  28. 2026-10-06 17:08 UTCGHSA enrichmentGHSA-m4cg-769c-m465
  29. 2026-10-06 17:08 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  30. 2026-10-06 15:39 UTCVendor advisory
  31. 2026-10-06 15:39 UTCGHSA enrichmentGHSA-m4cg-769c-m465
  32. 2026-10-06 15:19 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  33. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  34. 2026-10-04 23:23 UTCEPSS rescoreEPSS 0.2% · 6th percentile
  35. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  36. 2026-10-03 11:27 UTCVendor advisory
  37. 2026-10-03 11:27 UTCGHSA enrichmentGHSA-m4cg-769c-m465
  38. 2026-10-03 11:26 UTCNVD update
  39. 2026-10-03 11:12 UTCVendor advisory
  40. 2026-10-03 11:12 UTCGHSA enrichmentGHSA-m4cg-769c-m465
  41. 2026-10-03 11:10 UTCMITRE cvelistV5
  42. 2026-10-02 17:57 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  43. 2026-10-01 19:51 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  44. 2026-09-30 15:04 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  45. 2026-09-30 14:35 UTCEG score recompute
  46. 2026-09-30 14:35 UTCVendor advisory
  47. 2026-09-30 14:35 UTCGHSA enrichmentGHSA-m4cg-769c-m465
  48. 2026-09-28 15:21 UTCEG score recompute
  49. 2026-09-28 15:21 UTCVendor advisory
  50. 2026-09-28 15:21 UTCGHSA enrichmentGHSA-m4cg-769c-m465
  51. 2026-09-28 13:52 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  52. 2026-09-27 13:49 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  53. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.2% · 5th percentile
  54. 2026-09-25 11:30 UTCNVD update
  55. 2026-09-25 10:27 UTCEG score recompute
  56. 2026-09-25 10:27 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-98080?
CVE-2026-98080 is a medium-severity vulnerability; its CVE record was published on September 25, 2026. In the Linux kernel, the following vulnerability has been resolved: btrfs: do not force reloc root creation during qgroup_account_snapshot() [BUG] When running btrfs/252 with quota enabled through MKFS_OPTIONS="-O quota", it has a high chance to trigger the following kernel warning and flips the fs…
When was the CVE record for CVE-2026-98080 published?
The CVE record for CVE-2026-98080 was published on September 25, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 19, 2026; the record at its source may have been updated since.
Is CVE-2026-98080 actively exploited?
CVE-2026-98080 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (2nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-98080?
CVE-2026-98080 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-98080?
A fix for CVE-2026-98080 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-98080 are linked in the Vendor Advisories panel on this page.

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