CVE-2026-76957

HIGHNVD 7.87.8—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.8 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
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.

libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.

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
1%
KEV
Not listed

Published

August 20, 2026

Last Modified

September 8, 2026

Advisory Details (2)

Auto-updated Aug 20, 2026
No patch confirmed yet. Sources: github_pr.
github_pr

Prepare release 2.8.4 (part of #1328, ETA 2026-08-31)

Upstream fix in progress (PR #1329 · libexpat/libexpat, state=open)

https://github.com/libexpat/libexpat/pull/1329
github_pr

[CVE-REQUESTED] Protect custom encoding callbacks from parser re-entry

Upstream fix in progress (PR #1322 · libexpat/libexpat, state=open)

https://github.com/libexpat/libexpat/pull/1322

Vendor Advisories for CVE-2026-76957(3)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatexpat-main-2.8.4-0.1.hum12026-09-08redhat
redhatexpat-main-2.8.3-0.1.1.hum12026-08-27redhat

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 7 ecosystems)
Alpine:v3.21(1)
PackageVulnerable rangeFixed inDependents
expat—2.8.4-r0—
Alpine:v3.22(1)
PackageVulnerable rangeFixed inDependents
expat—2.8.4-r0—
Alpine:v3.23(1)
PackageVulnerable rangeFixed inDependents
expat—2.8.4-r0—
Alpine:v3.24(1)
PackageVulnerable rangeFixed inDependents
expat—2.8.4-r0—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
expat2.5.0-1, 2.5.0-1+deb12u1, 2.5.0-1+deb12u22.5.0-1+deb12u3—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
expat2.7.1-2 ... 2.8.4-1 (14 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
expat2.7.1-2 ... 2.8.3-1~deb13u1 (13 versions)2.8.4-1—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 37× in last 7d / 129× 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 132 total refreshes for this CVE.

  1. 2026-09-19 06:53 UTCVendor advisory
  2. 2026-09-19 06:53 UTCGHSA enrichment
  3. 2026-09-18 19:43 UTCEG score recompute
  4. 2026-09-18 19:43 UTCVendor advisory
  5. 2026-09-18 19:43 UTCGHSA enrichment
  6. 2026-09-18 19:28 UTCEPSS rescore
  7. 2026-09-18 08:36 UTCVendor advisory
  8. 2026-09-18 08:36 UTCGHSA enrichment
  9. 2026-09-17 21:25 UTCEG score recompute
  10. 2026-09-17 21:25 UTCVendor advisory
  11. 2026-09-17 21:25 UTCGHSA enrichment
  12. 2026-09-17 07:28 UTCVendor advisory
  13. 2026-09-17 07:28 UTCGHSA enrichment
  14. 2026-09-16 20:03 UTCEG score recompute
  15. 2026-09-16 20:03 UTCVendor advisory
  16. 2026-09-16 20:03 UTCGHSA enrichment
  17. 2026-09-16 14:08 UTCEPSS rescore
  18. 2026-09-16 06:59 UTCVendor advisory
  19. 2026-09-16 06:59 UTCGHSA enrichment
  20. 2026-09-15 19:53 UTCVendor advisory
  21. 2026-09-15 19:53 UTCGHSA enrichment
  22. 2026-09-15 08:45 UTCEG score recompute
  23. 2026-09-15 08:45 UTCVendor advisory
  24. 2026-09-15 08:44 UTCGHSA enrichment
  25. 2026-09-15 03:12 UTCEPSS rescore
Show 75 more
  1. 2026-09-14 21:36 UTCVendor advisory
  2. 2026-09-14 21:36 UTCGHSA enrichment
  3. 2026-09-14 10:28 UTCVendor advisory
  4. 2026-09-14 10:28 UTCGHSA enrichment
  5. 2026-09-13 23:22 UTCVendor advisory
  6. 2026-09-13 23:22 UTCGHSA enrichment
  7. 2026-09-13 12:16 UTCVendor advisory
  8. 2026-09-13 12:16 UTCGHSA enrichment
  9. 2026-09-13 01:10 UTCVendor advisory
  10. 2026-09-13 01:10 UTCGHSA enrichment
  11. 2026-09-12 14:04 UTCVendor advisory
  12. 2026-09-12 14:04 UTCGHSA enrichment
  13. 2026-09-12 02:58 UTCVendor advisory
  14. 2026-09-12 02:58 UTCGHSA enrichment
  15. 2026-09-11 15:52 UTCEG score recompute
  16. 2026-09-11 15:52 UTCVendor advisory
  17. 2026-09-11 15:52 UTCGHSA enrichment
  18. 2026-09-11 14:53 UTCEPSS rescore
  19. 2026-09-11 04:45 UTCVendor advisory
  20. 2026-09-11 04:45 UTCGHSA enrichment
  21. 2026-09-10 17:39 UTCEG score recompute
  22. 2026-09-10 17:39 UTCVendor advisory
  23. 2026-09-10 17:39 UTCGHSA enrichment
  24. 2026-09-10 09:35 UTCEPSS rescore
  25. 2026-09-10 06:33 UTCVendor advisory
  26. 2026-09-10 06:33 UTCGHSA enrichment
  27. 2026-09-09 19:27 UTCVendor advisory
  28. 2026-09-09 19:27 UTCGHSA enrichment
  29. 2026-09-09 08:20 UTCEG score recompute
  30. 2026-09-09 08:20 UTCVendor advisory
  31. 2026-09-09 08:20 UTCGHSA enrichment
  32. 2026-09-08 22:01 UTCEPSS rescore
  33. 2026-09-08 21:14 UTCEG score recompute▲ 2.90
  34. 2026-09-08 21:14 UTCVendor advisory
  35. 2026-09-08 21:14 UTCGHSA enrichment
  36. 2026-09-08 21:11 UTCNVD updateCVSS v3 → 7.8 · severity → HIGH
  37. 2026-09-07 16:53 UTCEG score recompute
  38. 2026-09-07 16:53 UTCVendor advisory
  39. 2026-09-07 16:53 UTCGHSA enrichment
  40. 2026-09-06 17:12 UTCEG score recompute
  41. 2026-09-06 17:12 UTCVendor advisory
  42. 2026-09-06 17:12 UTCGHSA enrichment
  43. 2026-09-06 13:48 UTCEPSS rescore
  44. 2026-09-05 17:28 UTCEG score recompute
  45. 2026-09-05 17:28 UTCVendor advisory
  46. 2026-09-05 17:28 UTCGHSA enrichment
  47. 2026-09-04 17:46 UTCEG score recompute
  48. 2026-09-04 17:46 UTCVendor advisory
  49. 2026-09-04 17:46 UTCGHSA enrichment
  50. 2026-09-04 05:07 UTCEPSS rescore
  51. 2026-09-03 18:05 UTCVendor advisory
  52. 2026-09-03 18:05 UTCGHSA enrichment
  53. 2026-09-03 13:39 UTCEG score recompute
  54. 2026-09-03 13:39 UTCVendor advisory
  55. 2026-09-03 13:39 UTCGHSA enrichment
  56. 2026-09-02 14:12 UTCEPSS rescore
  57. 2026-09-02 13:54 UTCVendor advisory
  58. 2026-09-02 13:54 UTCGHSA enrichment
  59. 2026-09-01 13:56 UTCEG score recompute
  60. 2026-09-01 13:56 UTCVendor advisory
  61. 2026-09-01 13:56 UTCGHSA enrichment
  62. 2026-09-01 13:54 UTCEPSS rescore
  63. 2026-09-01 04:40 UTCEPSS rescore
  64. 2026-09-01 04:40 UTCEPSS rescore
  65. 2026-08-31 14:10 UTCEG score recompute
  66. 2026-08-31 14:10 UTCVendor advisory
  67. 2026-08-31 14:09 UTCGHSA enrichment
  68. 2026-08-30 19:18 UTCEPSS rescore
  69. 2026-08-30 19:17 UTCEPSS rescore
  70. 2026-08-30 13:37 UTCEG score recompute
  71. 2026-08-30 13:37 UTCVendor advisory
  72. 2026-08-30 13:37 UTCGHSA enrichment
  73. 2026-08-30 01:22 UTCEPSS rescore
  74. 2026-08-29 13:54 UTCEG score recompute
  75. 2026-08-29 13:54 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-76957?
CVE-2026-76957 is a high vulnerability published on August 20, 2026. libexpat before 2.8.4 lacks handler call depth tracking with custom encoding callbacks. Thus, a use-after-free can occur. NOTE: this is similar to CVE-2026-50219, CVE-2026-56131 and CVE-2026-56412.
When was CVE-2026-76957 disclosed?
CVE-2026-76957 was first published in the National Vulnerability Database on August 20, 2026, with the most recent update on September 8, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-76957 actively exploited?
CVE-2026-76957 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 98.7% of all scored CVEs.
What is the CVSS score of CVE-2026-76957?
CVE-2026-76957 has a CVSS v3 base score of 7.8 (NVD).
How do I remediate CVE-2026-76957?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-76957, 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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