CVE-2026-48840

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Published 2026-05-30 · Modified 2026-06-03

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CVSS v3

5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v4 NEW

—

not yet in upstream

VIR risk

5.3

Description

Exim 4.88 before 4.99.4, in some proxy configurations, mishandles certain short payloads, leading to disclosure of uninitialized stack memory values to a client.

Predictions

Exploit likelihood

63%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

Mitigation details

Source: Debian Security Tracker · View original ↗ · DFSG

CVE-2026-48840 NameCVE-2026-48840 DescriptionExim 4.88 before 4.99.4, in some proxy configurations, mishandles certain short payloads, leading to disclosure of uninitialized stack memory values to a client. SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) ReferencesDSA-6309-1…

CVE-2026-48840

Name	CVE-2026-48840
Description	Exim 4.88 before 4.99.4, in some proxy configurations, mishandles certain short payloads, leading to disclosure of uninitialized stack memory values to a client.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DSA-6309-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
exim4 (PTS)	bullseye	4.94.2-7+deb11u3	vulnerable
	bullseye (security)	4.94.2-7+deb11u5	vulnerable
	bookworm	4.96-15+deb12u9	vulnerable
	bookworm (security)	4.96-15+deb12u10	fixed
	trixie	4.98.2-1+deb13u2	vulnerable
	trixie (security)	4.98.2-1+deb13u3	fixed
	forky	4.99.3-1	vulnerable
	sid	4.99.3-2	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Origin
exim4	source	bookworm	4.96-15+deb12u10	DSA-6309-1
exim4	source	trixie	4.98.2-1+deb13u3	DSA-6309-1
exim4	source	(unstable)	4.99.3-2

Notes

https://www.openwall.com/lists/oss-security/2026/05/29/3
https://www.exim.org/static/doc/security/EXIM-Security-2026-05-19.1/EXIM-Security-2026-05-19.1.txt
Fixed by: https://code.exim.org/exim/exim/commit/aae0c4c3fba1f7e50971ba250ddbbedb583d48a6 (exim-4.99.4)

Home - Debian Security - Source (Git)

Apply commands

text fix

Notes

https://www.openwall.com/lists/oss-security/2026/05/29/3https://www.exim.org/static/doc/security/EXIM-Security-2026-05-19.1/EXIM-Security-2026-05-19.1.txtFixed by: https://code.exim.org/exim/exim/commit/aae0c4c3fba1f7e50971ba250ddbbedb583d48a6 (exim-4.99.4)

OS impact

Debian Mixed 5 releases

Version	Status	Fixed in
trixie	Fixed	`4.98.2-1+deb13u3`
sid	Fixed	`4.99.3-2`
forky	Fixed	`4.99.3-2`
bullseye	Affected	—
bookworm	Fixed	`4.96-15+deb12u10`

Application impact

Vendor	Product	Versions	Fixed
exim	exim	`{"startIncluding":"4.88","endExcluding":"4.99.4"}`	`4.99.4`

References

CWEs

CWE-839

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.