CVE-2026-116738

HIGHPre-NVD 8.88.8
EchelonGraph scoreHIGH confidence

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

Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-10-27. A secondary CVSS source baseline 8.8; 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-2026-110486 (ENISA EUVD) · GHSA-rhj9-fcgr-5r62 (GitHub Security Advisories)Source: ENISA EUVD

8.8EG
EchelonGraph verdictPlan mitigationRemediate 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: 0.7%CVSS: 8.8Exploit: None knownExposed services: Not assessed

An upstream fix is merged but not yet released — mitigate (WAF / firewall / segmentation) until the release ships, then apply it.

VMime through 0.9.2 contains an integer underflow in the uuEncoder::decode function that allows remote attackers to trigger a stack-based buffer overflow via crafted uuencoded MIME parts. Attackers can send an email with a uuencoded line whose length character is 'b' but is not a 'begin' line, corrupting stack memory to crash the application or potentially execute code.

CVSS v3
8.8
EG Score
8.8HIGHhigh confidence
EG Risk
55
EG Risk 55/100

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)
Severity88% × 45%
Impact severity (EG Severity): CVSS 8.8 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.
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 total (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: An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high until it ships, then apply the release.
EPSS PROB
0.7%
EPSS %ILE
53rd
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 (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.

EG Severity
8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.7% 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 low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: 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).

An upstream fix is merged but not yet in a tagged release. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high until it ships, then apply the release.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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)3 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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 26, 2026

Last Modified

October 27, 2026

Advisory Details (6)

Auto-updated Oct 26, 2026
Upstream fix merged — awaiting tagged release. Sources: github_commit, github_pr.
Web page

VMime through 0.9.2 Stack-Based Buffer Overflow via uuencode Decoder | Advisories | VulnCheck

https://www.vulncheck.com/advisories/vmime-through-0.9.2-stack-based-buffer-overflow-via-uuencode-decoder
Web page

VMime uuencode decoder: an unsigned underflow of the read length drives an out-of-bounds write on the stack while decoding a crafted MIME body - HackMD

https://hackmd.io/@haindpwn/vmime-uuencode-decoder-oob-write
Web page

vmime/src/vmime/utility/encoder/uuEncoder.cpp at v0.9.2 · kisli/vmime · GitHub

https://github.com/kisli/vmime/blob/v0.9.2/src/vmime/utility/encoder/uuEncoder.cpp#L185-L190
Web page

GitHub - kisli/vmime: VMime Mail Library · GitHub

https://github.com/kisli/vmime
GitHub commit

commit e85925eddc63 (kisli/vmime)

Fix landed in kisli/vmime commit e85925eddc63 — awaiting tagged release

https://github.com/kisli/vmime/commit/e85925eddc638939f0eeb7ee55ec047d04a760d8
GitHub pull request

uuEncoder: fix out-of-bounds write and several decoding bugs

Fix merged in kisli/vmime PR #363 on 2026-10-23 — awaiting tagged release

https://github.com/kisli/vmime/pull/363

Vendor Advisories for CVE-2026-116738(1)

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. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  2. 2026-10-27 16:08 UTCGHSA enrichmentGHSA-rhj9-fcgr-5r62 · GitHub severity HIGH · GitHub CVSS 8.8
  3. 2026-10-27 15:28 UTCEG score recompute
  4. 2026-10-27 15:28 UTCGHSA enrichmentGHSA-rhj9-fcgr-5r62 · GitHub severity HIGH · GitHub CVSS 8.8
  5. 2026-10-27 14:43 UTCEG score recompute
  6. 2026-10-27 14:43 UTCGHSA enrichmentGHSA-rhj9-fcgr-5r62 · GitHub severity HIGH · GitHub CVSS 8.8
  7. 2026-10-26 23:01 UTCENISA EUVD ID recordedEUVD-2026-110486 · Source: ENISA EUVD
  8. 2026-10-26 22:39 UTCEG score recompute
  9. 2026-10-26 22:02 UTCEG score recomputeFirst assessed: 8.8 HIGH
  10. 2026-10-26 22:00 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-116738?
CVE-2026-116738 is a high-severity vulnerability; its CVE record was published on October 26, 2026. VMime through 0.9.2 contains an integer underflow in the uuEncoder::decode function that allows remote attackers to trigger a stack-based buffer overflow via crafted uuencoded MIME parts. Attackers can send an email with a uuencoded line whose length character is 'b' but is not a 'begin' line,…
When was CVE-2026-116738 made public?
CVE-2026-116738 was made public on October 23, 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 26, 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-2026-116738 actively exploited?
CVE-2026-116738 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (53rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-116738?
CVE-2026-116738 has a CVSS base score of 8.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-116738?
An upstream fix for CVE-2026-116738 has been merged but is not yet in a tagged release. Until it ships, restrict network exposure of the affected system or apply the vendor's mitigation, then update to the release that contains the fix. The vendor advisories EchelonGraph has for CVE-2026-116738 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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