CVE-2026-34001

HIGHPre-NVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

Score 7.8 from GitHub Security Advisory (severity: HIGH) published 2026-04-23. a secondary CVSS source baseline 7.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
7.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.8Exploit: None knownExposed: 0

A fix is available — apply it.

A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the X11 server can exploit this without user interaction, leading to a server crash and potentially enabling memory corruption. This could result in a denial of service or further compromise of the system.

CVSS v3
7.8
EG Score
7.8(medium)
EG Risk
35(Track)
EG Risk 35/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity78% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
18%
KEV
Not listed

Published

April 23, 2026

Last Modified

July 15, 2026

Advisory Details (7)

Auto-updated Apr 29, 2026
Patch available. Sources: redhat.
redhat Patch Available

2451109 – (CVE-2026-34001) CVE-2026-34001 xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption

Affected: Red Hat Enterprise Linux 9

https://bugzilla.redhat.com/show_bug.cgi?id=2451109
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-34001
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2026:11692
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:11388
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:11369
redhat Patch Available

Affected: Red Hat Enterprise Linux 10.

https://access.redhat.com/errata/RHSA-2026:11352
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:10739

Vendor Advisories for CVE-2026-34001(20)

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

Patch Availability(30)

Vendor / EcosystemFixed in / PatchReleasedSource
redhattigervnc-0:1.12.0-6.el8_6.172026-06-08redhat
redhattigervnc-0:1.1.0-25.el6_10.162026-06-04redhat
redhattigervnc-0:1.12.0-15.el8_8.172026-06-04redhat
redhattigervnc-0:1.11.0-8.el8_4.152026-06-04redhat
redhattigervnc-0:1.14.1-10.el9_62026-06-02redhat
redhattigervnc-0:1.8.0-36.el7_9.42026-06-02redhat
redhatxorg-x11-server-0:1.20.11-18.el8_82026-05-28redhat
redhatxorg-x11-server-Xwayland-0:21.1.3-2.el8_6.62026-05-28redhat
redhattigervnc-0:1.11.0-22.el9_0.172026-05-28redhat
redhatxorg-x11-server-0:1.20.10-4.el8_42026-05-28redhat
redhatxorg-x11-server-Xwayland-0:21.1.3-13.el8_82026-05-28redhat
redhatxorg-x11-server-0:1.20.11-13.el9_02026-05-28redhat
redhatxorg-x11-server-0:1.20.11-7.el8_62026-05-28redhat
redhatxorg-x11-server-Xwayland-0:21.1.3-10.el9_22026-05-26redhat
redhattigervnc-0:1.13.1-8.el9_4.92026-05-26redhat
redhatxorg-x11-server-0:1.20.4-34.el7_92026-05-26redhat
redhatxorg-x11-server-Xwayland-0:24.1.5-6.el10_02026-05-26redhat
redhatxorg-x11-server-0:1.20.11-20.el9_22026-05-26redhat
redhatxorg-x11-server-0:1.20.11-28.el9_42026-05-26redhat
redhatxorg-x11-server-Xwayland-0:22.1.9-8.el9_42026-05-26redhat
redhattigervnc-0:1.12.0-14.el9_2.142026-05-26redhat
redhatxorg-x11-server-0:1.20.11-33.el9_62026-05-26redhat
redhatxorg-x11-server-Xwayland-0:21.1.3-5.el9_02026-05-26redhat
redhatxorg-x11-server-Xwayland-0:23.2.7-6.el9_62026-05-26redhat
redhatxorg-x11-server-0:1.20.11-34.el9_82026-05-19redhat
redhatxorg-x11-server-Xwayland-0:24.1.9-4.el10_22026-05-19redhat
redhatxorg-x11-server-Xwayland-0:24.1.9-4.el9_82026-05-19redhat
redhattigervnc-0:1.15.0-7.el9_8.12026-05-19redhat
redhattigervnc-0:1.15.0-9.el8_102026-05-04redhat
redhatxorg-x11-server-0:1.20.11-28.el8_102026-04-29redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(7 across 4 ecosystems)
Debian:12(2)
PackageVulnerable rangeFixed inDependents
xorg-server2:21.1.7-3 ... 2:21.1.7-3+deb12u9 (12 versions)2:21.1.7-3+deb12u12—
xwayland2:22.1.9-1 ... 2:24.1.9-1 (23 versions)——
Debian:13(2)
PackageVulnerable rangeFixed inDependents
xorg-server2:21.1.16-1.3, 2:21.1.16-1.3+deb13u12:21.1.16-1.3+deb13u2—
xwayland2:24.1.10-1 ... 2:24.1.9-1 (6 versions)——
Debian:14(2)
PackageVulnerable rangeFixed inDependents
xorg-server2:21.1.16-1.3, 2:21.1.18-1, 2:21.1.18-2, 2:21.1.20-1, 2:21.1.21-12:21.1.22-1—
xwayland2:24.1.6-1, 2:24.1.8-1, 2:24.1.9-12:24.1.10-1—
Debian:11(1)
PackageVulnerable rangeFixed inDependents
xorg-server2:1.20.11-1 ... 2:21.1.9-1+hurd.1 (61 versions)——

Weakness Classification(1)

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

Additional Vendor Advisories

(16)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 7× in last 7d / 78× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 215 total refreshes for this CVE.

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

Frequently asked(5)

What is CVE-2026-34001?
CVE-2026-34001 is a high vulnerability published on April 23, 2026. A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the X11 server can exploit this without user interaction, leading to a server crash and potentially…
When was CVE-2026-34001 disclosed?
CVE-2026-34001 was first published in the National Vulnerability Database on April 23, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-34001 actively exploited?
CVE-2026-34001 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 82.1% of all scored CVEs.
What is the CVSS score of CVE-2026-34001?
CVE-2026-34001 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-34001?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-34001, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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