Exim before 4.99.3, in certain GnuTLS configurations, has a remotely reachable use-after-free in the BDAT body parsing path. It is triggered when a client sends a TLS close_notify mid-body during a CHUNKING transfer, followed by a final cleartext byte on the same TCP connection. This can lead to heap corruption. An unauthenticated network attacker exploiting this vulnerability could execute arbitrary code.
CVE-2026-45185
“—” beside the score: it is equal to NVD's CVSS score.
Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-05-12. NVD baseline CVSS 9.8; sources differ by 0.0.
Also known asEUVD-2026-29824 (ENISA EUVD) · GHSA-fhg4-whcv-f8v4 (GitHub Security Advisories)Source: ENISA EUVD
- Public exploit or proof-of-concept code is available
A fix is available — apply it.
- CVSS v3
- 9.8
- EG Score
- 9.8CRITICALmedium confidence
- EG Risk
- 75EG Risk 75/100
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)Severity98% × 45%Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation40% × 40%EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.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: 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
- 1.3%
- EPSS %ILE
- 69th
- 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 (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 1.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). 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).
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 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
May 12, 2026
Last Modified
May 28, 2026
Advisory Details (7)
Auto-updated Oct 8, 2026oss-security - Re: [EXIM-Security-2026-05-01.1] Security Release 4.99.3
http://www.openwall.com/lists/oss-security/2026/05/12/25Dead.Letter - How XBOW found an unauthenticated RCE on Exim | XBOW
https://xbow.com/blog/dead-letter-cve-2026-45185-xbow-found-rce-eximoss-security - [EXIM-Security-2026-05-01.1] Security Release 4.99.3
https://www.openwall.com/lists/oss-security/2026/05/12/4Dead.Letter (CVE-2026-45185) – How XBOW found an unauthenticated RCE on Exim | Hacker News
https://news.ycombinator.com/item?id=48111748Index of /static/doc/security/EXIM-Security-2026-05-01.1/
https://exim.org/static/doc/security/EXIM-Security-2026-05-01.1/Patch Availability(1)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | eximon4 (4.82-3ubuntu2.4+esm9) @ trusty | 2026-10-30 | ubuntu |
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
(4 across 4 ecosystems)
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| exim4 | 4.94.2-7, 4.94.2-7+deb11u1, 4.94.2-7+deb11u2, 4.94.2-7+deb11u3, 4.94.2-7+deb11u4 |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| exim4 | 4.96-15 ... 4.96-15+deb12u8 (9 versions) |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| exim4 | 4.98.2-1, 4.98.2-1+deb13u1 |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| exim4 | 4.98.2-1 ... 4.99~RC3-2 (27 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(1)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
Data Freshness Timeline
(refreshed 28× in last 7d / 82× 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.
Showing the most recent 100 of 539 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 439 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-10-30 10:03 UTCEG score recompute
- 2026-10-30 10:03 UTCVendor advisory
- 2026-10-30 10:03 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 1.3% · 69th percentile
- 2026-10-29 08:52 UTCEG score recompute
- 2026-10-29 08:51 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 1.3% · 69th percentile
- 2026-10-28 07:35 UTCEG score recompute
- 2026-10-28 07:35 UTCVendor advisory
- 2026-10-28 07:35 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 1.3% · 69th percentile
- 2026-10-27 06:24 UTCEG score recompute
- 2026-10-27 06:24 UTCVendor advisory
- 2026-10-27 06:24 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-26 16:31 UTCEPSS rescoreEPSS 1.3% · 69th percentile
- 2026-10-26 01:15 UTCEG score recompute
- 2026-10-26 01:15 UTCVendor advisory
- 2026-10-26 01:15 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 1.3% · 69th percentile
- 2026-10-25 14:27 UTCEG score recompute
- 2026-10-25 00:04 UTCEG score recompute
- 2026-10-25 00:04 UTCVendor advisory
- 2026-10-25 00:04 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-23 22:52 UTCEG score recompute
Show 75 moreShow fewer
- 2026-10-23 22:52 UTCVendor advisory
- 2026-10-23 22:52 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-22 21:35 UTCEG score recompute
- 2026-10-22 21:35 UTCVendor advisory
- 2026-10-22 21:35 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-21 20:18 UTCEG score recompute
- 2026-10-21 20:18 UTCVendor advisory
- 2026-10-21 20:18 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-20 19:06 UTCEG score recompute
- 2026-10-20 19:06 UTCVendor advisory
- 2026-10-20 19:06 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-19 17:53 UTCEG score recompute
- 2026-10-19 17:53 UTCVendor advisory
- 2026-10-19 17:52 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-18 16:40 UTCEG score recompute
- 2026-10-18 16:39 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-18 03:38 UTCEG score recompute
- 2026-10-17 20:21 UTCEG score recompute
- 2026-10-17 20:20 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-16 19:07 UTCEG score recompute
- 2026-10-16 19:07 UTCVendor advisory
- 2026-10-16 19:07 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-15 16:20 UTCEG score recompute
- 2026-10-15 16:20 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-14 10:31 UTCEG score recompute
- 2026-10-14 10:31 UTCVendor advisory
- 2026-10-14 10:30 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.9% · 60th percentile
- 2026-10-13 09:00 UTCEG score recompute
- 2026-10-13 08:59 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-12 16:04 UTCEG score recompute
- 2026-10-12 07:47 UTCVendor advisory
- 2026-10-12 07:47 UTCGHSA enrichmentGHSA-fhg4-whcv-f8v4 · GitHub severity CRITICAL · GitHub CVSS 9.8
- 2026-10-11 19:46 UTCEG score recompute
- 2026-10-11 17:01 UTCEG score recompute
- 2026-10-11 14:26 UTCEG score recompute
- 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.9% · 59th percentile
- 2026-09-23 17:53 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-20 20:15 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-18 19:28 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-17 19:31 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-16 14:08 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-16 05:15 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-13 16:47 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-12 15:01 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-11 14:53 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-11 09:37 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-10 09:34 UTCEPSS rescoreEPSS 1.2% · 67th percentile
- 2026-09-08 22:00 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-09-07 16:01 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-09-06 13:47 UTCEPSS rescoreEPSS 1.2% · 66th percentile
- 2026-09-04 05:06 UTCEPSS rescoreEPSS 1.2% · 66th percentile
Publicly available exploits
(2 references)Public exploit code is referenced for this CVE (1 GitHub PoC), as is 1 GitHub checker repository. A GitHub repository named or described as a checker or scanner checks whether a system is affected; it is not necessarily exploit code. Defenders should treat patch urgency accordingly.
- GitHub PoCMJ-bin/POC_CVE-2026-45185Published May 19, 2026
POC_CVE-2026-45185 for nuclei-templates
Open source ↗ - GitHub checkerliamromanis101/Dead.Letter-CVE-2026-45185Published May 12, 2026
Dead.Letter CVE-2026-45185 EXIM Vulnerability Detection Script
Open source ↗
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Frequently asked(5)
What is CVE-2026-45185?
When was the CVE record for CVE-2026-45185 published?
Is CVE-2026-45185 actively exploited?
What is the CVSS score of CVE-2026-45185?
How do I remediate CVE-2026-45185?
Dependency Blast Radius
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