CVE-2026-123976

MEDIUMPre-NVD 5.55.5
EchelonGraph scoreHIGH confidence

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

Score 5.5 from GitHub Security Advisory (severity: MODERATE) published 2026-11-06. A secondary CVSS source baseline 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source

Also known asEUVD-2026-118395 (ENISA EUVD) · GHSA-26mh-qcgf-vfgg (GitHub Security Advisories)Source: ENISA EUVD

5.5EG
EchelonGraph verdictMonitorNo release containing the referenced fix is confirmed: check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 5.5Exploit: None knownExposed services: Not assessed

A fix is referenced (a reference tagged "Patch", often a source commit), but no release containing it is confirmed — find the release that contains it; until it is applied, mitigate (WAF / firewall / segmentation).

EDFbrowser before 2.16 contains an out-of-bounds write vulnerability in check_edf_file() that allows attackers to overflow the 256-element annot_ch array by supplying excessive annotation signals. Attackers can craft an EDF+ or BDF+ file with more than 256 annotation signals to overwrite edfhdrblock members, including the signal parameter pointer, crashing the application when opened.

CVSS v3
5.5
EG Score
5.5MEDIUMhigh confidence
EG Risk
25
EG Risk 25/100

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)
Severity55% × 45%
Impact severity (EG Severity): CVSS 5.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.
EPSS PROB
0.1%
EPSS %ILE
1st
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 (5.5): severity, escalated by confirmed exploitation. This CVE's 5.5 is its impact severity (EG Severity), not escalated.

EG Severity
5.5 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-12). 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.No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.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 referenced, but no release containing it is confirmed. Check the referenced fix and the vendor's advisory for a release that contains it; until one is applied, restrict network exposure of the affected system or apply the vendor's mitigation on your normal schedule.

Exploitation none (CISA Vulnrichment) · Automatable no (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)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

No released fix is confirmed on this page, but CISA's timeline does not wait for a fix's release: it starts when an agency identifies the flaw on an asset and updates the CDM Agency and Federal Dashboard, and the directive counts patching, decommissioning the system or another action as remediation. Until a fixed release is applied, mitigate as this page's verdict says. In the directive's words, “Fix on system upgrade” means that, “unless conditions change”, the vulnerability “should be remediated the next time the vulnerable asset receives a scheduled major upgrade or rebuild”: its timelines are “dynamic as facts change”, and a KEV listing shortens them.

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

November 6, 2026

Last Modified

November 12, 2026

Advisory Details (6)

Auto-updated Nov 6, 2026
Fix referenced — no release confirmed yet.
Web page

EDFbrowser before 2.16 Out-of-Bounds Write via check_edf_file() Annotation Signals | Advisories | VulnCheck

https://www.vulncheck.com/advisories/edfbrowser-before-2.16-out-of-bounds-write-via-check-edf-file-annotation-signals
Web page

Teuniz / EDFbrowser · GitLab

https://gitlab.com/Teuniz/EDFbrowser
Web page

global.h · v2.15 · Teuniz / EDFbrowser · GitLab

https://gitlab.com/Teuniz/EDFbrowser/-/blob/v2.15/global.h#L250
Web page

check_edf_file.c · v2.15 · Teuniz / EDFbrowser · GitLab

https://gitlab.com/Teuniz/EDFbrowser/-/blob/v2.15/check_edf_file.c#L686-L708
Web page

v2.16 · Tags · Teuniz / EDFbrowser · GitLab

https://gitlab.com/Teuniz/EDFbrowser/-/tags/v2.16
Web page

- Release v2.16. (f64cec4a) · Commits · Teuniz / EDFbrowser · GitLab

https://gitlab.com/Teuniz/EDFbrowser/-/commit/f64cec4a22af34adb7bbdf5fec12cb3a880ddc5a

Vendor Advisories for CVE-2026-123976(1)

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

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
edfbrowser2.00+dfsg-1 ... 2.15+dfsg-1 (13 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
edfbrowser2.12+dfsg-1, 2.13+dfsg-1, 2.14+dfsg-1, 2.15+dfsg-1
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
edfbrowser2.12+dfsg-1, 2.13+dfsg-1, 2.14+dfsg-1, 2.15+dfsg-1
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 12× in last 7d / 14× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-13 16:50 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  2. 2026-11-12 21:50 UTCEchelonGraph re-scored
  3. 2026-11-12 21:50 UTCGHSA enrichmentGHSA-26mh-qcgf-vfgg · GitHub severity MODERATE · GitHub CVSS 5.5
  4. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  5. 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  6. 2026-11-11 07:29 UTCGHSA enrichmentGHSA-26mh-qcgf-vfgg · GitHub severity MODERATE · GitHub CVSS 5.5
  7. 2026-11-10 20:35 UTCEchelonGraph re-scored
  8. 2026-11-10 20:35 UTCGHSA enrichmentGHSA-26mh-qcgf-vfgg · GitHub severity MODERATE · GitHub CVSS 5.5
  9. 2026-11-10 20:15 UTCEchelonGraph re-scored
  10. 2026-11-10 20:15 UTCGHSA enrichmentGHSA-26mh-qcgf-vfgg · GitHub severity MODERATE · GitHub CVSS 5.5
  11. 2026-11-10 16:42 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  12. 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  13. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  14. 2026-11-08 08:54 UTCEchelonGraph re-scored
  15. 2026-11-08 08:54 UTCGHSA enrichmentGHSA-26mh-qcgf-vfgg · GitHub severity MODERATE · GitHub CVSS 5.5
  16. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  17. 2026-11-06 19:04 UTCENISA EUVD ID recordedEUVD-2026-118395 · Source: ENISA EUVD
  18. 2026-11-06 18:28 UTCEchelonGraph re-scored
  19. 2026-11-06 18:03 UTCEchelonGraph re-scoredFirst assessed: 5.5 MEDIUM
  20. 2026-11-06 18:02 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-123976?
CVE-2026-123976 is a medium-severity vulnerability; its CVE record was published on November 6, 2026. EDFbrowser before 2.16 contains an out-of-bounds write vulnerability in check_edf_file() that allows attackers to overflow the 256-element annot_ch array by supplying excessive annotation signals. Attackers can craft an EDF+ or BDF+ file with more than 256 annotation signals to overwrite…
When was CVE-2026-123976 made public?
CVE-2026-123976 was made public on November 5, 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 November 6, 2026. EchelonGraph's copy of the record carries a last-modified date of November 12, 2026; the record at its source may have been updated since.
Is CVE-2026-123976 actively exploited?
CVE-2026-123976 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-2026-123976?
CVE-2026-123976 has a CVSS base score of 5.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-123976?
A fix for CVE-2026-123976 is referenced (a reference tagged "Patch", often a source commit), but EchelonGraph has no release containing it on record. Check that reference and the vendor's advisory for a release that contains the fix and update to it; until then, restrict network exposure of the affected system or apply the vendor's mitigation. The vendor advisories EchelonGraph has for CVE-2026-123976 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-123976

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