Описание
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix introduces evhttp_parse_headers_impl_ and a temporary trailer header list. An unauthenticated remote attacker can place security-sensitive fields in trailers so that an upstream proxy and the libevent application interpret different effective headers, enabling header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning. The fix parses trailers into a temporary header list and discards them instead of merging them into req->input_headers. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
A flaw was found in Libevent, an event notification library. An unauthenticated remote attacker can exploit a vulnerability where chunked HTTP (Hypertext Transfer Protocol) trailers are incorrectly merged into request headers. This allows the attacker to place security-sensitive fields in trailers, causing an upstream proxy and the Libevent application to interpret different effective headers. This can lead to header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning.
Отчет
Red Hat ships libevent in multiple products including Red Hat Enterprise Linux, RHIVOS, and as part of RHCOS in OpenShift. All shipped versions are prior to the fix in 2.1.13 and are affected by this vulnerability.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | libevent | Fix deferred | ||
| Red Hat Enterprise Linux 6 | libevent | Fix deferred | ||
| Red Hat Enterprise Linux 6 | libevent2 | Fix deferred | ||
| Red Hat Enterprise Linux 7 | libevent | Fix deferred | ||
| Red Hat Enterprise Linux 8 | libevent | Fix deferred | ||
| Red Hat Enterprise Linux 9 | libevent | Affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Fix deferred | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Fix deferred | ||
| Red Hat Hardened Images | libevent-main-2.1.12-19.1.hum1 | Fixed | RHSA-2026:60853 | 29.08.2026 |
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Дополнительная информация
Статус:
EPSS
6.5 Medium
CVSS3
Связанные уязвимости
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix introduces evhttp_parse_headers_impl_ and a temporary trailer header list. An unauthenticated remote attacker can place security-sensitive fields in trailers so that an upstream proxy and the libevent application interpret different effective headers, enabling header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning. The fix parses trailers into a temporary header list and discards them instead of merging them into req->input_headers. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent processes chunked HTTP trailers in http.c through evhttp_read_trailer and merges them into request headers. The fix introduces evhttp_parse_headers_impl_ and a temporary trailer header list. An unauthenticated remote attacker can place security-sensitive fields in trailers so that an upstream proxy and the libevent application interpret different effective headers, enabling header smuggling, authorization bypass, proxy-header spoofing, or cache poisoning. The fix parses trailers into a temporary header list and discards them instead of merging them into req->input_headers. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.
Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-a ...
EPSS
6.5 Medium
CVSS3