CVE-2026-77214

HIGHPre-NVD 8.28.2
EchelonGraph scoreHIGH confidence

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

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2026-10-07. The CNA's CVSS baseline 8.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: the CNA's CVSS, EPSS, GitHub Security Advisory
Trending — 4 sources updated this week

Also known asEUVD-2026-94368 (ENISA EUVD) · GHSA-8xfx-9m5m-pgcp (GitHub Security Advisories)Source: ENISA EUVD

8.2EG
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).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 8.2Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

libexpat before commit 13c5f63 contains a heap buffer over-read vulnerability in xmlparse.c. XML_ParseBuffer advances the parse buffer end with parser->m_bufferEnd += len using a caller-supplied length that is not validated against the allocated buffer size, so repeated XML_ParseBuffer calls move m_bufferEnd past the end of the heap allocation and subsequent parsing reads out of bounds. Reaching this path requires a parse buffer to already be present; otherwise XML_ParseBuffer returns XML_ERROR_NO_BUFFER. A buffer is present after a prior call to XML_GetBuffer, either directly (the common case) or indirectly through a prior XML_Parse call that allocates the buffer internally. The over-read discloses adjacent heap memory to the calling application, recovering heap pointers, libc function pointers, and code pointers sufficient to defeat ASLR and build further exploitation primitives.

CVSS v3
8.2
EG Score
8.2HIGHhigh confidence
EG Risk
52
EG Risk 52/100

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)
Severity82% × 45%
Impact severity (EG Severity): CVSS 8.2 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high.
EPSS PROB
0.3%
EPSS %ILE
24th
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 (8.2): severity, escalated by confirmed exploitation. This CVE's 8.2 is its impact severity (EG Severity), not escalated.

EG Severity
8.2 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-26). 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 or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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 or medium mission impact; Attend at high (mission-essential systems).

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

Exploitation none (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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

October 7, 2026

Last Modified

October 27, 2026

Advisory Details (3)

Auto-updated Oct 7, 2026
Patch available. Sources: github_pr, github_commit.
Web page

libexpat Heap Buffer Over-read in xmlparse.c via XML_ParseBuffer | Advisories | VulnCheck

https://www.vulncheck.com/advisories/libexpat-heap-buffer-over-read-in-xmlparse-c-via-xml-parsebuffer
GitHub commit

commit 13c5f63a7f1c (libexpat/libexpat)

Fix landed in libexpat/libexpat commit 13c5f63a7f1c — awaiting tagged release

https://github.com/libexpat/libexpat/commit/13c5f63a7f1c52c2feee3b16a1134d4fb68e9ea0
GitHub pull request

[CVE-2026-77214] lib: Validate `len` against buffer capacity in `XML_ParseBuffer`

Fix merged in libexpat/libexpat PR #1393 on 2026-09-25 — awaiting tagged release

https://github.com/libexpat/libexpat/pull/1393

Patch Availability(4)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatexpat-0:2.7.3-1.el10_2.72026-10-22redhat
redhatexpat-0:2.5.0-6.el9_8.72026-10-22redhat
redhatexpat-main-2.9.0-1.hum12026-10-20redhat
redhatexpat-main-2.8.5-1.2.hum12026-10-07redhat

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

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
expat2.5.0-1 ... 2.9.0-1 (34 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
expat2.7.1-2 ... 2.9.0-1 (18 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
expat2.7.1-2 ... 2.8.5-2 (17 versions)
  • every version up to 2.9.0-1: fixed in 2.9.0-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 73× 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.

  1. 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  2. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  3. 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  4. 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  5. 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  6. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  7. 2026-10-27 10:25 UTCEG score recompute
  8. 2026-10-27 10:25 UTCVendor advisory
  9. 2026-10-27 10:25 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  10. 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  11. 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  12. 2026-10-25 14:01 UTCEG score recompute
  13. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  14. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  15. 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  16. 2026-10-22 11:37 UTCEG score recompute
  17. 2026-10-22 11:37 UTCVendor advisory
  18. 2026-10-22 11:37 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  19. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.5% · 45th percentile
  20. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  21. 2026-10-20 08:13 UTCEG score recompute
  22. 2026-10-20 08:13 UTCVendor advisory
  23. 2026-10-20 08:12 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  24. 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  25. 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
Show 48 more
  1. 2026-10-18 03:12 UTCEG score recompute
  2. 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  3. 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  4. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  5. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  6. 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  7. 2026-10-13 07:00 UTCEG score recompute
  8. 2026-10-13 07:00 UTCVendor advisory
  9. 2026-10-13 07:00 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  10. 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  11. 2026-10-12 15:37 UTCEG score recompute
  12. 2026-10-12 01:10 UTCVendor advisory
  13. 2026-10-12 01:09 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  14. 2026-10-11 19:23 UTCEG score recompute
  15. 2026-10-11 16:39 UTCEG score recompute
  16. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  17. 2026-10-11 13:42 UTCEG score recompute
  18. 2026-10-11 13:42 UTCVendor advisory
  19. 2026-10-11 13:42 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  20. 2026-10-11 02:09 UTCEG score recompute
  21. 2026-10-11 02:09 UTCVendor advisory
  22. 2026-10-11 02:09 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  23. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  24. 2026-10-10 14:44 UTCVendor advisory
  25. 2026-10-10 14:43 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  26. 2026-10-10 03:22 UTCEG score recompute
  27. 2026-10-10 03:22 UTCVendor advisory
  28. 2026-10-10 03:22 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  29. 2026-10-10 02:40 UTCEG score recompute
  30. 2026-10-10 02:40 UTCVendor advisory
  31. 2026-10-10 02:40 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  32. 2026-10-10 01:20 UTCEG score recompute
  33. 2026-10-10 01:20 UTCVendor advisory
  34. 2026-10-10 01:20 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  35. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  36. 2026-10-09 13:58 UTCVendor advisory
  37. 2026-10-09 13:58 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  38. 2026-10-09 02:34 UTCEG score recompute
  39. 2026-10-09 02:34 UTCVendor advisory
  40. 2026-10-09 02:34 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  41. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.5% · 44th percentile
  42. 2026-10-08 15:12 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  43. 2026-10-08 03:34 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  44. 2026-10-07 16:12 UTCEG score recompute
  45. 2026-10-07 16:12 UTCGHSA enrichmentGHSA-8xfx-9m5m-pgcp · GitHub severity HIGH · GitHub CVSS 8.2
  46. 2026-10-07 15:30 UTCEG score recompute
  47. 2026-10-07 14:42 UTCEG score recomputeFirst assessed: 8.2 HIGH
  48. 2026-10-07 14:41 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-77214?
CVE-2026-77214 is a high-severity vulnerability; its CVE record was published on October 7, 2026. libexpat before commit 13c5f63 contains a heap buffer over-read vulnerability in xmlparse.c. XML_ParseBuffer advances the parse buffer end with parser->m_bufferEnd += len using a caller-supplied length that is not validated against the allocated buffer size, so repeated XML_ParseBuffer calls move…
When was CVE-2026-77214 made public?
CVE-2026-77214 was made public on September 24, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on October 7, 2026. EchelonGraph's copy of the record carries a last-modified date of October 27, 2026; the record at its source may have been updated since.
Is CVE-2026-77214 actively exploited?
CVE-2026-77214 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (24th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77214?
CVE-2026-77214 has a CVSS base score of 8.2 (the CNA's own assessment, by vulncheck; NVD's own analysis pending).
How do I remediate CVE-2026-77214?
A fix for CVE-2026-77214 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-77214 are linked in the Vendor Advisories panel on this page.

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