Improper Input Validation The advisory has been revoked - it doesn't affect any version of package haproxy.src (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-RHEL10-HAPROXYSRC-12614799
- published11 Sept 2025
- disclosed17 Aug 2021
Introduced: 17 Aug 2021
CVE-2021-39242 (opens in a new tab)Amendment
The Red Hat security team deemed this advisory irrelevant for RHEL:10.
NVD Description
Note: Versions mentioned in the description apply only to the upstream haproxy.src package and not the haproxy.src package as distributed by RHEL.
An issue was discovered in HAProxy 2.2 before 2.2.16, 2.3 before 2.3.13, and 2.4 before 2.4.3. It can lead to a situation with an attacker-controlled HTTP Host header, because a mismatch between Host and authority is mishandled.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1995112
- https://access.redhat.com/security/cve/CVE-2021-39242
- https://git.haproxy.org/?p=haproxy.git;a=commit;h=b5d2b9e154d78e4075db163826c5e0f6d31b2ab1
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4ALECUZDIMT5FYGP6V6PVSI4BKVZTZWN/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/RPNY4WZIQUAUOCLIMUPC37AQWNXTWIQM/
- https://www.mail-archive.com/haproxy@formilux.org/msg41041.html
- https://git.haproxy.org/?p=haproxy.git%3Ba=commit%3Bh=b5d2b9e154d78e4075db163826c5e0f6d31b2ab1
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ALECUZDIMT5FYGP6V6PVSI4BKVZTZWN/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPNY4WZIQUAUOCLIMUPC37AQWNXTWIQM/
- https://www.debian.org/security/2021/dsa-4960
- https://www.mail-archive.com/haproxy%40formilux.org/msg41041.html