CVE-2026-76886Public exploitNetwork attack vector

Denial of service via EAX length truncation

Published Aug 19, 2026 · Updated Aug 20, 2026

Heap-based buffer overflow in the C12.22 dissector in Wireshark before 4.4.18 and 4.6.8 allows attackers to crash the process via crafted traffic. The dissector passes packet-derived 32-bit lengths into 16-bit EAX CMAC helpers; in cleartext-authentication mode the truncated sizes wrap, causing an undersized heap allocation followed by oversized memcpy writes in dCMAC(). Reachability requires reassembled C12.22 TCP/1153 traffic, enabled c1222.decrypt, and a matching decryption-table entry; public proof-of-concept material demonstrated a crash, but disclosure or code execution was not demonstrated.

CVSS severity8.1
High
EPSS probability0.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in the C12.22 dissector in Wireshark before 4.4.18 and 4.6.8 allows attackers to crash the process via crafted traffic. The dissector passes packet-derived 32-bit lengths into 16-bit EAX CMAC helpers; in cleartext-authentication mode the truncated sizes wrap, causing an undersized heap allocation followed by oversized memcpy writes in dCMAC(). Reachability requires reassembled C12.22 TCP/1153 traffic, enabled c1222.decrypt, and a matching decryption-table entry; public proof-of-concept material demonstrated a crash, but disclosure or code execution was not demonstrated.

The record

CVE
CVE-2026-76886
Published
Aug 19, 2026
Updated
Aug 20, 2026
Vendor
Wireshark Foundation
Product
Wireshark
Classifications
CWE-122, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=4.4.0 <4.4.18
  2. Affected versionversion=4.6.0 <4.6.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Wireshark Foundation · Wiresharkversion=4.4.0 <4.4.18; version=4.6.0 <4.6.8

Published CVSS scores

8.1GitLab Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1499Endpoint Denial of Service

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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