CVE-2026-93834

HIGHPre-NVD 8.88.8
EchelonGraph scoreMEDIUM confidence

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

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-09-25. A secondary CVSS source baseline 8.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 4 sources updated this weekElevated

Also known asEUVD-2026-87092 (ENISA EUVD) · GHSA-86c2-8qp8-q2vh (GitHub Security Advisories)Source: ENISA EUVD

8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • Public exploit or proof-of-concept code is available
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 8.8Exploit: Public PoCExposed services: Not assessed

A fix is available — apply it.

A use-after-free vulnerability was found in QEMU's 9pfs subsystem. A race condition between the main thread and a worker thread when processing concurrent Tlcreate and Twalk requests allows a malicious guest user to craft a fid path containing stale heap data, bypassing directory traversal restrictions and escaping the shared directory boundary. This can lead to arbitrary host file read/write and code execution (VM escape) as the QEMU process user.

CVSS v3
8.8
EG Score
8.8HIGHmedium confidence
EG Risk
56
EG Risk 56/100

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)
Severity88% × 45%
Impact severity (EG Severity): CVSS 8.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.4%
EPSS %ILE
34th
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 (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.

EG Severity
8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-30). 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, Track* at medium and Attend at high mission impact.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, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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)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 Vulnrichment) · Technical impact total (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

September 25, 2026

Last Modified

October 31, 2026

Advisory Details (3)

Auto-updated Sep 25, 2026
Patch available. Sources: redhat.
Web page

VM guest escape via 9p filesystem exploit (#4491) · Issues · QEMU / QEMU · GitLab

https://gitlab.com/qemu-project/qemu/-/work_items/4491
Red Hat

2537939 – (CVE-2026-93834) CVE-2026-93834 qemu-kvm: 9pfs: use-after-free race in Tlcreate/Twalk allows VM guest escape

https://bugzilla.redhat.com/show_bug.cgi?id=2537939
Red HatMentions a patch (unverified)

CVE-2026-93834 - Red Hat Customer Portal

Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a

https://access.redhat.com/security/cve/CVE-2026-93834

Vendor Advisories for CVE-2026-93834(2)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
qemu1:10.0.0+ds-1 ... 1:9.2.2+ds-1~bpo12+1 (200 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
qemu1:10.0.10+ds-0+deb13u1 ... 1:11.1.2+ds-1 (67 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
qemu1:10.0.2+ds-2 ... 1:11.1.1+ds-1 (56 versions)
  • every version up to 1:11.1.2+ds-1: fixed in 1:11.1.2+ds-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 13× in last 7d / 94× 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 100 of 133 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. None are among the latest 100 rows. The 33 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:36 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  3. 2026-10-31 08:26 UTCEG score recompute
  4. 2026-10-31 08:26 UTCVendor advisory
  5. 2026-10-31 08:26 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  6. 2026-10-31 08:04 UTCEG score recompute
  7. 2026-10-31 08:04 UTCVendor advisory
  8. 2026-10-31 08:04 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  9. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  10. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  11. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  12. 2026-10-27 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  13. 2026-10-26 16:33 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  14. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.4% · 34th percentile
  15. 2026-10-25 15:34 UTCEG score recompute
  16. 2026-10-25 15:34 UTCVendor advisory
  17. 2026-10-25 15:34 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  18. 2026-10-25 13:49 UTCEG score recompute
  19. 2026-10-24 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  20. 2026-10-23 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  21. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  22. 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  23. 2026-10-20 17:47 UTCEG score recompute
  24. 2026-10-20 17:46 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  25. 2026-10-20 16:34 UTCEPSS rescoreEPSS 0.4% · 30th percentile
Show 75 more
  1. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  2. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  3. 2026-10-18 02:58 UTCEG score recompute
  4. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  5. 2026-10-16 16:45 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  6. 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.4% · 30th percentile
  7. 2026-10-14 16:34 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  8. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  9. 2026-10-13 04:22 UTCEG score recompute
  10. 2026-10-13 04:22 UTCVendor advisory
  11. 2026-10-13 04:22 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  12. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  13. 2026-10-12 14:42 UTCEG score recompute
  14. 2026-10-12 02:08 UTCVendor advisory
  15. 2026-10-12 02:07 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  16. 2026-10-11 19:12 UTCEG score recompute
  17. 2026-10-11 16:28 UTCEG score recompute
  18. 2026-10-11 14:32 UTCEG score recompute
  19. 2026-10-11 14:32 UTCVendor advisory
  20. 2026-10-11 14:32 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  21. 2026-10-11 13:50 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  22. 2026-10-11 13:41 UTCEG score recompute
  23. 2026-10-11 02:57 UTCEG score recompute
  24. 2026-10-11 02:57 UTCVendor advisory
  25. 2026-10-11 02:56 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  26. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  27. 2026-10-10 15:17 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  28. 2026-10-10 03:42 UTCEG score recompute
  29. 2026-10-10 03:42 UTCVendor advisory
  30. 2026-10-10 03:42 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  31. 2026-10-09 20:08 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  32. 2026-10-09 16:07 UTCVendor advisory
  33. 2026-10-09 16:06 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  34. 2026-10-09 04:32 UTCEG score recompute
  35. 2026-10-09 04:32 UTCVendor advisory
  36. 2026-10-09 04:32 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  37. 2026-10-08 17:14 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  38. 2026-10-08 16:57 UTCVendor advisory
  39. 2026-10-08 16:57 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  40. 2026-10-08 05:16 UTCEG score recompute
  41. 2026-10-08 05:16 UTCVendor advisory
  42. 2026-10-08 05:16 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  43. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  44. 2026-10-07 17:40 UTCVendor advisory
  45. 2026-10-07 17:40 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  46. 2026-10-07 04:23 UTCVendor advisory
  47. 2026-10-07 04:23 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  48. 2026-10-06 16:48 UTCEG score recompute
  49. 2026-10-06 16:48 UTCVendor advisory
  50. 2026-10-06 16:48 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  51. 2026-10-06 15:19 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  52. 2026-10-06 05:12 UTCEG score recompute
  53. 2026-10-06 05:12 UTCVendor advisory
  54. 2026-10-06 05:12 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  55. 2026-10-05 17:44 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  56. 2026-10-05 17:30 UTCVendor advisory
  57. 2026-10-05 17:30 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  58. 2026-10-05 05:54 UTCEG score recompute
  59. 2026-10-05 05:54 UTCVendor advisory
  60. 2026-10-05 05:54 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  61. 2026-10-04 23:23 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  62. 2026-10-04 18:16 UTCVendor advisory
  63. 2026-10-04 18:16 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  64. 2026-10-04 06:41 UTCVendor advisory
  65. 2026-10-04 06:41 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  66. 2026-10-03 19:07 UTCEG score recompute
  67. 2026-10-03 19:07 UTCVendor advisory
  68. 2026-10-03 19:07 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  69. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.4% · 29th percentile
  70. 2026-10-03 07:32 UTCVendor advisory
  71. 2026-10-03 07:31 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  72. 2026-10-02 19:54 UTCEG score recompute
  73. 2026-10-02 19:54 UTCVendor advisory
  74. 2026-10-02 19:54 UTCGHSA enrichmentGHSA-86c2-8qp8-q2vh · GitHub severity HIGH · GitHub CVSS 8.8
  75. 2026-10-02 08:19 UTCVendor advisory

Publicly available exploits

(1 reference)

Public exploit code is referenced for this CVE (1 GitHub PoC). Defenders should treat patch urgency accordingly.

  • GitHub PoCsuominen/CVE-2026-93834
    Published Sep 26, 2026

    Tracking the QEMU CVE-2026-93834 9pfs fid-path use-after-free guest-to-host escape

    Open source ↗

Frequently asked(5)

What is CVE-2026-93834?
CVE-2026-93834 is a high-severity vulnerability; its CVE record was published on September 25, 2026. A use-after-free vulnerability was found in QEMU's 9pfs subsystem. A race condition between the main thread and a worker thread when processing concurrent Tlcreate and Twalk requests allows a malicious guest user to craft a fid path containing stale heap data, bypassing directory traversal…
When was CVE-2026-93834 made public?
CVE-2026-93834 was made public on September 22, 2026: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on September 25, 2026. EchelonGraph's copy of the record carries a last-modified date of October 31, 2026; the record at its source may have been updated since.
Is CVE-2026-93834 actively exploited?
CVE-2026-93834 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (34th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-93834?
CVE-2026-93834 has a CVSS base score of 8.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-93834?
A fix for CVE-2026-93834 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-93834 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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