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% (1st percentile of EPSS-scored CVEs). 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: 0.1%CVSS: 7.8Exploit: None knownExposed services: Not assessed

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
7.8HIGHmedium confidence
EG Risk
35
EG Risk 35/100CISA SSVC

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%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.1%
EPSS %ILE
1st
KEV
Not listed

CISA SSVCTrack 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). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 20, 2026

Last Modified

September 8, 2026

Advisory Details (2)

Auto-updated Aug 20, 2026
Patch available. 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(4)

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

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibexpat1-dev (2.1.0-7ubuntu0.16.04.5+esm14) @ xenial2026-10-05ubuntu
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 rangeFix by version rangeDependents
expat—
  • every version up to 2.8.4-r0: fixed in 2.8.4-r0
—
Alpine:v3.22(1)
PackageVulnerable rangeFix by version rangeDependents
expat—
  • every version up to 2.8.4-r0: fixed in 2.8.4-r0
—
Alpine:v3.23(1)
PackageVulnerable rangeFix by version rangeDependents
expat—
  • every version up to 2.8.4-r0: fixed in 2.8.4-r0
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
expat—
  • every version up to 2.8.4-r0: fixed in 2.8.4-r0
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
expat2.5.0-1, 2.5.0-1+deb12u1, 2.5.0-1+deb12u2
  • every version up to 2.5.0-1+deb12u3: fixed in 2.5.0-1+deb12u3
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
expat2.7.1-2 ... 2.8.5-2 (17 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
expat2.7.1-2 ... 2.8.3-1~deb13u1 (13 versions)
  • every version up to 2.8.4-1: fixed in 2.8.4-1
—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

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 35× in last 7d / 154× 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. 2026-10-05 08:28 UTCEG score recompute
  2. 2026-10-05 08:28 UTCVendor advisory
  3. 2026-10-05 08:28 UTCGHSA enrichment
  4. 2026-10-04 23:22 UTCEPSS rescore
  5. 2026-10-04 21:21 UTCVendor advisory
  6. 2026-10-04 21:21 UTCGHSA enrichment
  7. 2026-10-04 06:30 UTCVendor advisory
  8. 2026-10-04 06:30 UTCGHSA enrichment
  9. 2026-10-03 19:24 UTCVendor advisory
  10. 2026-10-03 19:24 UTCGHSA enrichment
  11. 2026-10-03 06:51 UTCVendor advisory
  12. 2026-10-03 06:51 UTCGHSA enrichment
  13. 2026-10-02 19:45 UTCEG score recompute
  14. 2026-10-02 19:45 UTCVendor advisory
  15. 2026-10-02 19:45 UTCGHSA enrichment
  16. 2026-10-02 08:39 UTCVendor advisory
  17. 2026-10-02 08:39 UTCGHSA enrichment
  18. 2026-10-01 21:33 UTCEG score recompute
  19. 2026-10-01 21:33 UTCVendor advisory
  20. 2026-10-01 21:33 UTCGHSA enrichment
  21. 2026-10-01 19:50 UTCEPSS rescore
  22. 2026-10-01 07:39 UTCVendor advisory
  23. 2026-10-01 07:39 UTCGHSA enrichment
  24. 2026-09-30 20:33 UTCEG score recompute
  25. 2026-09-30 20:33 UTCVendor advisory
Show 75 more
  1. 2026-09-30 20:33 UTCGHSA enrichment
  2. 2026-09-30 08:27 UTCVendor advisory
  3. 2026-09-30 08:27 UTCGHSA enrichment
  4. 2026-09-29 02:02 UTCEG score recompute
  5. 2026-09-29 02:02 UTCVendor advisory
  6. 2026-09-29 02:02 UTCGHSA enrichment
  7. 2026-09-28 14:17 UTCEG score recompute
  8. 2026-09-28 14:17 UTCVendor advisory
  9. 2026-09-28 14:17 UTCGHSA enrichment
  10. 2026-09-28 13:52 UTCEPSS rescore
  11. 2026-09-28 03:10 UTCVendor advisory
  12. 2026-09-28 03:10 UTCGHSA enrichment
  13. 2026-09-27 16:04 UTCEG score recompute
  14. 2026-09-27 16:04 UTCVendor advisory
  15. 2026-09-27 16:04 UTCGHSA enrichment
  16. 2026-09-27 13:48 UTCEPSS rescore
  17. 2026-09-27 04:13 UTCEG score recompute
  18. 2026-09-27 04:13 UTCVendor advisory
  19. 2026-09-27 04:13 UTCGHSA enrichment
  20. 2026-09-26 15:59 UTCEPSS rescore
  21. 2026-09-26 00:28 UTCEPSS rescore
  22. 2026-09-25 11:52 UTCVendor advisory
  23. 2026-09-25 11:52 UTCGHSA enrichment
  24. 2026-09-25 00:46 UTCEG score recompute
  25. 2026-09-25 00:46 UTCVendor advisory
  26. 2026-09-25 00:46 UTCGHSA enrichment
  27. 2026-09-24 14:04 UTCEPSS rescore
  28. 2026-09-24 10:42 UTCVendor advisory
  29. 2026-09-24 10:42 UTCGHSA enrichment
  30. 2026-09-23 23:28 UTCEG score recompute
  31. 2026-09-23 23:28 UTCVendor advisory
  32. 2026-09-23 23:28 UTCGHSA enrichment
  33. 2026-09-23 17:54 UTCEPSS rescore
  34. 2026-09-23 11:55 UTCVendor advisory
  35. 2026-09-23 11:55 UTCGHSA enrichment
  36. 2026-09-23 00:49 UTCEG score recompute
  37. 2026-09-23 00:49 UTCVendor advisory
  38. 2026-09-23 00:49 UTCGHSA enrichment
  39. 2026-09-22 16:01 UTCEPSS rescore
  40. 2026-09-22 13:43 UTCVendor advisory
  41. 2026-09-22 13:42 UTCGHSA enrichment
  42. 2026-09-22 02:36 UTCEG score recompute
  43. 2026-09-22 02:36 UTCVendor advisory
  44. 2026-09-22 02:36 UTCGHSA enrichment
  45. 2026-09-21 21:09 UTCEPSS rescore
  46. 2026-09-21 15:29 UTCVendor advisory
  47. 2026-09-21 15:29 UTCGHSA enrichment
  48. 2026-09-21 04:03 UTCEG score recompute
  49. 2026-09-21 04:03 UTCVendor advisory
  50. 2026-09-21 04:03 UTCGHSA enrichment
  51. 2026-09-20 20:16 UTCEPSS rescore
  52. 2026-09-20 16:57 UTCVendor advisory
  53. 2026-09-20 16:57 UTCGHSA enrichment
  54. 2026-09-20 05:37 UTCVendor advisory
  55. 2026-09-20 05:37 UTCGHSA enrichment
  56. 2026-09-19 18:31 UTCEG score recompute
  57. 2026-09-19 18:31 UTCVendor advisory
  58. 2026-09-19 18:31 UTCGHSA enrichment
  59. 2026-09-19 06:53 UTCVendor advisory
  60. 2026-09-19 06:53 UTCGHSA enrichment
  61. 2026-09-18 19:43 UTCEG score recompute
  62. 2026-09-18 19:43 UTCVendor advisory
  63. 2026-09-18 19:43 UTCGHSA enrichment
  64. 2026-09-18 19:28 UTCEPSS rescore
  65. 2026-09-18 08:36 UTCVendor advisory
  66. 2026-09-18 08:36 UTCGHSA enrichment
  67. 2026-09-17 21:25 UTCEG score recompute
  68. 2026-09-17 21:25 UTCVendor advisory
  69. 2026-09-17 21:25 UTCGHSA enrichment
  70. 2026-09-17 07:28 UTCVendor advisory
  71. 2026-09-17 07:28 UTCGHSA enrichment
  72. 2026-09-16 20:03 UTCEG score recompute
  73. 2026-09-16 20:03 UTCVendor advisory
  74. 2026-09-16 20:03 UTCGHSA enrichment
  75. 2026-09-16 14:08 UTCEPSS rescore

Related CVEs(same product + same vendor + same CWE)

Same vendor

4 shown

redhat:RHSA-2026:65568 · redhat:RHSA-2026:60451 · ubuntu:USN-8813-1

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 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 0.1% probability of exploitation in the next 30 days (1st percentile of EPSS-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?
A fix for CVE-2026-76957 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-76957 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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