CentOS Linux 6 [TuxCare] Security Update: libevent / libevent-devel / libevent-doc / libevent-headers Multiple Vulnerabilities (CENTOS6:CLSA-2026:1792747726)

critical Nessus Plugin ID 372090

Synopsis

The CentOS Linux host is missing one or more security updates.

Description

The CentOS Linux 6 host has packages installed that are affected by multiple vulnerabilities as referenced in the TuxCare CENTOS6:CLSA-2026:1792747726 advisory.

- The name_parse function in evdns.c in libevent before 2.1.6-beta allows remote attackers to have unspecified impact via vectors involving the label_len variable, which triggers an out-of-bounds stack read. (CVE-2016-10195)

- The search_make_new function in evdns.c in libevent before 2.1.6-beta allows attackers to cause a denial of service (out-of-bounds read) via an empty hostname. (CVE-2016-10197)

- Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, the libevent evhttp parser in http.c inconsistently handles duplicate Transfer-Encoding headers, comma-separated Transfer-Encoding values, and bare line feeds in chunked framing. evhttp_find_header can select only the first header, evhttp_check_transfer_encoding_ was absent so the previous whole-string comparison fails to recognize valid lists ending in chunked, and evhttp_handle_chunked_read uses EVBUFFER_EOL_CRLF rather than EVBUFFER_EOL_CRLF_STRICT, accepting bare LF chunk terminators. When libevent is deployed behind a proxy that frames the same request differently, an unauthenticated remote attacker can desynchronize request boundaries and smuggle a second request, potentially bypassing access controls or poisoning caches. This issue is fixed in versions 2.1.13 and 2.2.2-alpha. (CVE-2026-63382)

- Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has an incorrect integer conversion in event_tagging.c when evtag_unmarshal_header uses evtag_decode_int to decode an attacker-controlled uint32 payload length and returns it as a signed int. Values above INT_MAX become negative or truncated, and evtag_unmarshal_string can use the converted value in allocation sizing, producing a wrapped large allocation request and denial of service. This issue is fixed in versions 2.1.13 and 2.2.2-alpha. (CVE-2026-63384)

- Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent has two HTTP parsing weaknesses in http.c. evhttp_decode_uri_internal decodes percent-encoded %00 bytes into literal NUL characters, which can cause downstream C string operations to truncate a path and bypass validation performed on a different representation. evhttp_header_is_valid_value also accepts obsolete line folding in header values containing carriage return or line feed characters, allowing a proxy and libevent to interpret headers differently and enabling header injection or access control bypass. The CRLF header acceptance is fixed in versions 2.1.13 and 2.2.2-alpha, but the reviewed patches do not clearly remediate the URI NUL-truncation condition. (CVE-2026-63385)

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages based on the guidance in TuxCare advisory CENTOS6:CLSA-2026:1792747726.

Plugin Details

Severity: Critical

ID: 372090

File Name: tuxcare_centos_6_CLSA-2026-1792747726.nasl

Version: 1.1

Type: Local

Agent: unix

Family: CentOS Local Security Checks

Published: 10/26/2026

Updated: 10/26/2026

Supported Sensors: Continuous Assessment, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5

Percentile: 93.02

Vendor

Vendor Severity: Critical

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.9

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2016-10195

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.8

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C

CVSS v4

Risk Factor: Critical

Base Score: 9.2

Threat Score: 8.1

Threat Vector: CVSS:4.0/E:P

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:L/SI:L/SA:N

CVSS Score Source: CVE-2026-63385

Vulnerability Information

Required KB Items: Host/OS/extended-third-party, Host/local_checks_enabled, Host/CentOS/release, Host/CentOS/rpm-list

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 10/23/2026

Vulnerability Publication Date: 1/31/2017

Reference Information

CVE: CVE-2016-10195, CVE-2016-10197, CVE-2026-63382, CVE-2026-63384, CVE-2026-63385, CVE-2026-63387

CLSA: 2026:1792747726

Detections

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