Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update
Affects Red HatSource GCVE Database
Not known to be exploited.
Data as of 3 Nov 2026, 04:46 UTC
Rated by Threat Radar · No CVSS score from NVD or the CNA
Exploitation evidence
Disclosed: evidence found.
CVE published 3 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2 Nov 2026.
What to do
AI-suggested
Red Hat has released updated nghttp2 packages as part of Red Hat Hardened Images RPMs to address this vulnerability. Users should apply these updates to remediate the issue. Additionally, configuring web application firewalls or load balancers to drop incoming HTTP/1.1 requests containing both Upgrade and Content-Length headers can block malformed traffic at the network edge before it reaches the vulnerable proxy, without affecting legitimate users.
Description
A vulnerability in the nghttp2 nghttpx proxy allows remote attackers to perform HTTP request smuggling and cross-client response-queue poisoning. This occurs due to ambiguous forwarding of HTTP/1.1 Upgrade requests containing a Content-Length header to reusable keep-alive backend connections. The issue is rated moderate severity because exploitation requires high attack complexity on the backend server. Mitigation involves configuring WAFs or load balancers to drop HTTP/1.1 requests containing both Upgrade and Content-Length headers to block malformed traffic before it reaches the proxy. Red Hat has issued an update for Red Hat Hardened Images RPMs including nghttp2 packages to address this vulnerability.
References
- access.redhat.com/errata/RHSA-2026:35454 (opens in a new tab)
- access.redhat.com/security/cve/CVE-2026-58055 (opens in a new tab)
- access.redhat.com/security/updates/classification/ (opens in a new tab)
- images.redhat.com (opens in a new tab)
- security.access.redhat.com/data/csaf/v2/advisories/2026/rhsa-2026_35454.json (opens in a new tab)