CVE-2021-47175

HIGHNVD 7.17.1
EchelonGraph scoreMEDIUM confidence

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

Score 7.1 from GitHub Security Advisory (severity: HIGH) published 2024-03-25. NVD baseline CVSS 7.1; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 3 sources updated this week

Also known asEUVD-2021-33823 (ENISA EUVD) · GHSA-36f6-8vpp-3cqp (GitHub Security Advisories)Source: ENISA EUVD

7.1EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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

net/sched: fq_pie: fix OOB access in the traffic path

the following script:

# tc qdisc add dev eth0 handle 0x1 root fq_pie flows 2 # tc qdisc add dev eth0 clsact # tc filter add dev eth0 egress matchall action skbedit priority 0x10002 # ping 192.0.2.2 -I eth0 -c2 -w1 -q

produces the following splat:

BUG: KASAN: slab-out-of-bounds in fq_pie_qdisc_enqueue+0x1314/0x19d0 [sch_fq_pie] Read of size 4 at addr ffff888171306924 by task ping/942

CPU: 3 PID: 942 Comm: ping Not tainted 5.12.0+ #441 Hardware name: Red Hat KVM, BIOS 1.11.1-4.module+el8.1.0+4066+0f1aadab 04/01/2014 Call Trace: dump_stack+0x92/0xc1 print_address_description.constprop.7+0x1a/0x150 kasan_report.cold.13+0x7f/0x111 fq_pie_qdisc_enqueue+0x1314/0x19d0 [sch_fq_pie] __dev_queue_xmit+0x1034/0x2b10 ip_finish_output2+0xc62/0x2120 __ip_finish_output+0x553/0xea0 ip_output+0x1ca/0x4d0 ip_send_skb+0x37/0xa0 raw_sendmsg+0x1c4b/0x2d00 sock_sendmsg+0xdb/0x110 __sys_sendto+0x1d7/0x2b0 __x64_sys_sendto+0xdd/0x1b0 do_syscall_64+0x3c/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7fe69735c3eb Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 75 42 2c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56 41 89 RSP: 002b:00007fff06d7fb38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 000055e961413700 RCX: 00007fe69735c3eb RDX: 0000000000000040 RSI: 000055e961413700 RDI: 0000000000000003 RBP: 0000000000000040 R08: 000055e961410500 R09: 0000000000000010 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff06d81260 R13: 00007fff06d7fb40 R14: 00007fff06d7fc30 R15: 000055e96140f0a0

Allocated by task 917: kasan_save_stack+0x19/0x40 __kasan_kmalloc+0x7f/0xa0 __kmalloc_node+0x139/0x280 fq_pie_init+0x555/0x8e8 [sch_fq_pie] qdisc_create+0x407/0x11b0 tc_modify_qdisc+0x3c2/0x17e0 rtnetlink_rcv_msg+0x346/0x8e0 netlink_rcv_skb+0x120/0x380 netlink_unicast+0x439/0x630 netlink_sendmsg+0x719/0xbf0 sock_sendmsg+0xe2/0x110 ____sys_sendmsg+0x5ba/0x890 ___sys_sendmsg+0xe9/0x160 __sys_sendmsg+0xd3/0x170 do_syscall_64+0x3c/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae

The buggy address belongs to the object at ffff888171306800 which belongs to the cache kmalloc-256 of size 256 The buggy address is located 36 bytes to the right of 256-byte region [ffff888171306800, ffff888171306900) The buggy address belongs to the page: page:00000000bcfb624e refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x171306 head:00000000bcfb624e order:1 compound_mapcount:0 flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) raw: 0017ffffc0010200 dead000000000100 dead000000000122 ffff888100042b40 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected

Memory state around the buggy address: ffff888171306800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff888171306880: 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc fc >ffff888171306900: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^ ffff888171306980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ffff888171306a00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

fix fq_pie traffic path to avoid selecting 'q->flows + q->flows_cnt' as a valid flow: it's an address beyond the allocated memory.

CVSS v3
7.1
EG Score
7.1HIGHmedium confidence
EG Risk
32
EG Risk 32/100

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)
Severity71% × 45%
Impact severity (EG Severity): CVSS 7.1 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (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
0.2%
EPSS %ILE
15th
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 (7.1): severity, escalated by confirmed exploitation. This CVE's 7.1 is its impact severity (EG Severity), not escalated.

EG Severity
7.1 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-28). 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 every mission impact level.CISA BOD 26-04: 60 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 every mission impact level.

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

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (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)60 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 Vulnrichment) · Technical impact partial (CISA Vulnrichment). 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

March 25, 2024

Last Modified

August 5, 2026

Advisory Details (3)

Auto-updated Aug 5, 2026
Patch available.
Web page

net/sched: fq_pie: fix OOB access in the traffic path - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e70f7a11876a1a788ceadf75e9e5f7af2c868680
Web page

net/sched: fq_pie: fix OOB access in the traffic path - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/7a1bdec12e43e29cc34a4394590337069d8812ce
Web page

net/sched: fq_pie: fix OOB access in the traffic path - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/e6294c06e7c62ffdd5bf3df696d3a4fcbb753d3c

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.10.46-1: fixed in 5.10.46-1
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.14.6-1: fixed in 5.14.6-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.14.6-1: fixed in 5.14.6-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux—
  • every version up to 5.14.6-1: fixed in 5.14.6-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 9× in last 7d / 38× 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.

Showing the most recent 97 of 215 refreshes on record for this CVE.

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. 3 repeat rows among the latest 100 are merged into the row they repeat. The 118 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-02 16:38 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  2. 2026-11-01 16:30 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  3. 2026-10-31 16:29 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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  5. 2026-10-29 16:29 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  6. 2026-10-28 21:39 UTCEG score recompute
  7. 2026-10-28 21:39 UTCGHSA enrichmentGHSA-36f6-8vpp-3cqp · GitHub severity HIGH · GitHub CVSS 7.1
  8. 2026-10-28 16:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  9. 2026-10-27 16:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  10. 2026-10-26 16:28 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  11. 2026-10-25 18:18 UTCEG score recompute
  12. 2026-10-25 16:29 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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  14. 2026-10-23 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  15. 2026-10-21 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  16. 2026-10-21 08:34 UTCEG score recompute
  17. 2026-10-21 08:34 UTCGHSA enrichmentGHSA-36f6-8vpp-3cqp · GitHub severity HIGH · GitHub CVSS 7.1
  18. 2026-10-20 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  19. 2026-10-19 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  20. 2026-10-19 12:55 UTCOSV refresh
  21. 2026-10-18 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  22. 2026-10-18 08:49 UTCEG score recompute
  23. 2026-10-17 16:29 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  24. 2026-10-16 16:34 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  25. 2026-10-15 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
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  1. 2026-10-14 16:29 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  2. 2026-10-13 16:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  3. 2026-10-12 19:05 UTCEG score recompute
  4. 2026-10-12 16:30 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  5. 2026-10-11 23:31 UTCEG score recompute
  6. 2026-10-11 13:44 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  7. 2026-10-10 19:56 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  8. 2026-10-09 20:04 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  9. 2026-10-08 16:40 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  10. 2026-10-07 23:45 UTCEPSS rescoreEPSS 0.2% · 14th percentile
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  15. 2026-10-02 16:23 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  16. 2026-09-30 15:45 UTCEG score recompute
  17. 2026-09-30 15:00 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  18. 2026-09-29 15:15 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  19. 2026-09-28 13:47 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  20. 2026-09-26 20:03 UTCOSV refresh
  21. 2026-09-26 15:54 UTCEPSS rescoreEPSS 0.2% · 13th percentile
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  36. 2026-09-08 21:57 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  37. 2026-09-07 15:58 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  38. 2026-09-07 05:18 UTCOSV refresh
  39. 2026-09-06 13:45 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  40. 2026-09-05 15:25 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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  45. 2026-08-30 19:14 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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  54. 2026-08-20 15:31 UTCOSV refresh
  55. 2026-08-19 17:01 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  56. 2026-08-18 13:45 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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  60. 2026-08-15 01:27 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  61. 2026-08-13 21:57 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  62. 2026-08-12 13:48 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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  64. 2026-08-09 13:44 UTCEPSS rescoreEPSS 0.2% · 15th percentile
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  68. 2026-08-05 19:15 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  69. 2026-08-05 09:42 UTCEG score recompute
  70. 2026-08-05 09:42 UTCGHSA enrichmentGHSA-36f6-8vpp-3cqp · GitHub severity HIGH · GitHub CVSS 7.1
  71. 2026-08-04 15:06 UTCEPSS rescoreEPSS 0.2% · 15th percentile
  72. 2026-08-04 12:20 UTCEG score recompute

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2021-47175?
CVE-2021-47175 is a high-severity vulnerability; its CVE record was published on March 25, 2024. In the Linux kernel, the following vulnerability has been resolved: net/sched: fq_pie: fix OOB access in the traffic path the following script: tc qdisc add dev eth0 handle 0x1 root fq_pie flows 2 tc qdisc add dev eth0 clsact tc filter add dev eth0 egress matchall action skbedit priority 0x10002…
When was the CVE record for CVE-2021-47175 published?
The CVE record for CVE-2021-47175 was published on March 25, 2024. 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 August 5, 2026; the record at its source may have been updated since.
Is CVE-2021-47175 actively exploited?
CVE-2021-47175 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2021-47175?
CVE-2021-47175 has a CVSS v3 base score of 7.1 (NVD).
How do I remediate CVE-2021-47175?
A fix for CVE-2021-47175 is available: update to the fixed version the vendor names in its advisory.

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