CVE-2026-117610

MEDIUMPre-NVD 5.95.9
EchelonGraph scoreHIGH confidence

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

Score 5.9 from GitHub Security Advisory (severity: HIGH) published 2026-10-28. A secondary CVSS source baseline 5.9; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: GitHub Security Advisory, a secondary CVSS source
Trending — 5 sources updated this week

Also known asEUVD-2026-111545 (ENISA EUVD) · GHSA-v4h5-6r69-76p3 (GitHub Security Advisories)Source: ENISA EUVD

5.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.4%CVSS: 5.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

libexpat through 2.9.0 contains a NULL pointer dereference vulnerability in externalEntityInitProcessor2() in lib/xmlparse.c that mishandles the XML_TOK_NONE token from empty input. Attackers who control stream chunking can force an empty non-final first parse on an external entity subparser, causing a later parse to crash the application.

CVSS v3
5.9
EG Score
5.9MEDIUMhigh confidence
EG Risk
27
EG Risk 27/100

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)
Severity59% × 45%
Impact severity (EG Severity): CVSS 5.9 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0% × 40%
No KEV listing, EG-KEV tier or EPSS when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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.
EPSS PROB
0.4%
EPSS %ILE
36th
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 (5.9): severity, escalated by confirmed exploitation. This CVE's 5.9 is its impact severity (EG Severity), not escalated.

EG Severity
5.9 MEDIUMCVSS-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. 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 every mission impact level.CISA BOD 26-04: 60 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 every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from 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)60 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's BOD 26-04 default) · Technical impact partial (CVSS v4.0 confidentiality and integrity impact neither High). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” 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 28, 2026

Last Modified

October 28, 2026

Advisory Details (5)

Auto-updated Oct 28, 2026
Patch available. Sources: github_pr, github_commit.
Web page

libexpat through 2.9.0 NULL Pointer Dereference via External Entity Subparser | Advisories | VulnCheck

https://www.vulncheck.com/advisories/libexpat-through-2.9.0-null-pointer-dereference-via-external-entity-subparser
Web page

GitHub - libexpat/libexpat: :herb: Fast streaming XML parser written in C99 with >90% test coverage; moved from SourceForge to GitHub · GitHub

https://github.com/libexpat/libexpat
Web page

libexpat/expat/lib/xmlparse.c at a76b1174c1ea52abb639a4c69d52b630a8a106a2 · libexpat/libexpat · GitHub

https://github.com/libexpat/libexpat/blob/a76b1174c1ea52abb639a4c69d52b630a8a106a2/expat/lib/xmlparse.c#L3468-L3510
GitHub commit

commit 7b0d50e4b1d1 (libexpat/libexpat)

Fix landed in libexpat/libexpat commit 7b0d50e4b1d1 — awaiting tagged release

https://github.com/libexpat/libexpat/commit/7b0d50e4b1d16fafd55876260701e04279a7489d
GitHub pull request

[CVE-REQUESTED] lib: Fix initial non-final empty subparser call with a handler

Upstream fix in progress (PR #1444 · libexpat/libexpat, state=open)

https://github.com/libexpat/libexpat/pull/1444

Vendor Advisories for CVE-2026-117610(2)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 10× 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. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  2. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  3. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  4. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.4% · 36th percentile
  5. 2026-10-28 15:26 UTCEG score recompute
  6. 2026-10-28 15:26 UTCGHSA enrichmentGHSA-v4h5-6r69-76p3 · GitHub severity HIGH · GitHub CVSS 5.9
  7. 2026-10-28 03:28 UTCEG score recompute
  8. 2026-10-28 03:01 UTCENISA EUVD ID recordedEUVD-2026-111545 · Source: ENISA EUVD
  9. 2026-10-28 02:25 UTCEG score recomputeFirst assessed: 5.9 MEDIUM
  10. 2026-10-28 02:24 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-117610?
CVE-2026-117610 is a medium-severity vulnerability; its CVE record was published on October 28, 2026. libexpat through 2.9.0 contains a NULL pointer dereference vulnerability in externalEntityInitProcessor2() in lib/xmlparse.c that mishandles the XML_TOK_NONE token from empty input. Attackers who control stream chunking can force an empty non-final first parse on an external entity subparser,…
When was CVE-2026-117610 made public?
CVE-2026-117610 was made public on October 26, 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 28, 2026. EchelonGraph's copy of the record carries a last-modified date of October 28, 2026; the record at its source may have been updated since.
Is CVE-2026-117610 actively exploited?
CVE-2026-117610 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.4% probability of exploitation in the next 30 days (36th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-117610?
CVE-2026-117610 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-117610?
A fix for CVE-2026-117610 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-117610 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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