CVE-2010-1194: The match_component function in smtp-tls.c in libESMTP 1.0.3.r1, and possibly other versions including 1.0.4,

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MEDIUM 6.8WATCHLISTDOWNGRADE

CVE-2010-1194 is a medium-severity flaw (CVSS 6.8) affecting libesmtp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The match_component function in smtp-tls.c in libESMTP 1.0.3.r1, and possibly other versions including 1.0.4, treats two strings as equal if one is a substring of the other, which allows remote attackers to spoof trusted certificates via a crafted subjectAltName.

Why this priority

On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.8 (Medium)
EPSS exploit chance	1.4% (top 28%)
CISA exploited list	No
Weakness	CWE-310
Published	2010-03-31
Last modified	2026-06-16

Publisher (CNA): Canonical Ltd. · Vendor: stafford.uklinux

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2010-03-31 18:00 UTCPublished CVE record published
2026-06-16 23:17 UTCUpdated Record last modified

stafford.uklinux libesmtp DOWNGRADE

Affected: 0.1 · 0.1 a · 0.2 · 0.3 · 0.4 · 0.5 · 0.6 · 0.6 a

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.1

1. Check installed version

apt-cache policy libesmtp || rpm -q libesmtp || libesmtp --version

2. No fixed release: DOWNGRADE to a release before 0.1 (Debian / Ubuntu)

apt-cache madison libesmtp sudo apt install libesmtp=<VERSION_BEFORE_0.1> sudo apt-mark hold libesmtp

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list libesmtp sudo dnf downgrade libesmtp-<VERSION_BEFORE_0.1> sudo dnf versionlock add libesmtp

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2010-1194?

libesmtp: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2010-1194 being exploited?

CVE-2010-1194 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2010-1194 affect?

CVE-2010-1194 affects libesmtp. Severity is medium (CVSS 6.8). The match_component function in smtp-tls.c in libESMTP 1.0.3.r1, and possibly other versions including 1.0.4, treats two strings as equal if one is a substring of the other, which allows remote attackers to spoof trusted certificates via a

How urgent is CVE-2010-1194?

Priority 47/100. On your watchlist

Related CVEs

CVE-2019-19977 CRITICAL 9.8 UPGRADE libESMTP through 1.0.6 mishandles domain copying into a fixed-size buffer in ntlm_build_type_2 in ntlm/ntlmstr
CVE-2010-1192 MEDIUM 6.8 UPGRADE libESMTP, probably 1.0.4 and earlier, does not properly handle a '\0' character in a domain name in the subjec
CVE-2002-1090 HIGH 7.5 UPGRADE Buffer overflow in read_smtp_response of protocol.c in libesmtp before 0.8.11 allows a remote SMTP server to (

References

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