CVE-2026-6533Public exploit

Denial of service via unbounded LZ77 output

Published Apr 30, 2026 · Updated Apr 30, 2026

Resource exhaustion in Wireshark 4.4.9 through 4.4.14 and 4.6.0 through 4.6.4 allows attackers to crash Wireshark via malformed SMB2 data. The do_uncompress function in epan/tvbuff_lz77.c limits compressed input but does not cap decompressed output, so a crafted back-reference drives roughly 4.29 billion byte-copy iterations. Exploitation requires the target to capture an injected packet or a user to open a crafted trace, causing a hang, excessive CPU consumption, or a crash.

CVSS severity5.5
Medium
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in Wireshark 4.4.9 through 4.4.14 and 4.6.0 through 4.6.4 allows attackers to crash Wireshark via malformed SMB2 data. The do_uncompress function in epan/tvbuff_lz77.c limits compressed input but does not cap decompressed output, so a crafted back-reference drives roughly 4.29 billion byte-copy iterations. Exploitation requires the target to capture an injected packet or a user to open a crafted trace, causing a hang, excessive CPU consumption, or a crash.

The record

CVE
CVE-2026-6533
Published
Apr 30, 2026
Updated
Apr 30, 2026
Vendor
Wireshark Foundation
Product
Wireshark
Classifications
CWE-1325, CAPEC-130, T1499.004
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 30, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 30, 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=4.4.9 <4.4.15
  2. Affected versionversion=4.6.0 <4.6.5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Wireshark Foundation · Wiresharkversion=4.4.9 <4.4.15; version=4.6.0 <4.6.5

Published CVSS scores

5.5GitLab Inc.CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/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)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1325Improperly Controlled Sequential Memory Allocation
CAPEC-130Excessive Allocation
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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