Libevent up to 2.1.12/2.2.2-alpha event_tagging.c decode_tag_internal out-of-bounds

CVSS Meta Temp Score
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CTI Interest Score
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6.0$0-$5k0.00

Summaryinfo

A vulnerability was found in Libevent up to 2.1.12/2.2.2-alpha. It has been rated as critical. This affects the function decode_tag_internal of the file event_tagging.c. Performing a manipulation results in out-of-bounds. This vulnerability was named CVE-2026-63383. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical has been found in Libevent up to 2.1.12/2.2.2-alpha. This affects the function decode_tag_internal of the file event_tagging.c. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

Libevent is an event notification library. Prior to 2.1.13 and 2.2.2-alpha, libevent can read beyond a contiguous evbuffer region in event_tagging.c when decode_tag_internal requests at most five bytes from evbuffer_pullup but iterates using the full logical buffer length. A fragmented evbuffer containing a six-byte malformed tag can therefore advance past the pullup window and trigger an out-of-bounds read, which can crash a process that decodes attacker-controlled tagged RPC data. This issue is fixed in versions 2.1.13 and 2.2.2-alpha.

The advisory is shared at github.com. This vulnerability is uniquely identified as CVE-2026-63383 since 07/16/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 343966 (Fedora 44 : libevent (2026-72d10c874d)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 2.1.13 or 2.2.2-alpha eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (343966), EUVD (EUVD-2026-63502) and CERT Bund (WID-SEC-2026-3419). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • RESF Rocky Linux
  • SUSE Linux
  • SUSE openSUSE
  • Ubuntu Linux
  • Oracle Linux
  • IBM i

Productinfo

Name

Version

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 6.3
VulDB Meta Temp Score: 6.0

VulDB Base Score: 6.3
VulDB Temp Score: 6.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 343966
Nessus Name: Fedora 44 : libevent (2026-72d10c874d)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Libevent 2.1.13/2.2.2-alpha

Timelineinfo

07/16/2026 CVE reserved
08/20/2026 +35 days Advisory disclosed
08/20/2026 +0 days VulDB entry created
10/01/2026 +41 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-63383 (🔒)
GCVE (CVE): GCVE-0-2026-63383
GCVE (VulDB): GCVE-100-393813
EUVD: 🔒
CERT Bund: WID-SEC-2026-3419 - Red Hat Enterprise Linux (corosync, libevent, libsoup): Mehrere Schwachstellen

Entryinfo

Created: 08/20/2026 20:11
Updated: 10/01/2026 00:08
Changes: 08/20/2026 20:11 (67), 08/20/2026 21:56 (1), 09/09/2026 15:11 (2), 09/21/2026 18:04 (7), 09/24/2026 15:32 (1), 10/01/2026 00:08 (1)
Complete: 🔍
Cache ID: 216::103

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