Application crash via truncated fixext input
Published Mar 26, 2026 · Updated Mar 26, 2026
An out-of-bounds read in shamaton msgpack allows remote attackers to crash applications via truncated MessagePack fixext data. The ext/time decoder's ReadSize1 path reads the second byte without first confirming that the input contains at least two bytes, so a lone 0xd4-0xd8 format byte triggers a Go index-out-of-range panic. Exposure requires an application to decode attacker-controlled MessagePack data; the consequence is termination of that process, not data access or modification.
Summary
What happened
An out-of-bounds read in shamaton msgpack allows remote attackers to crash applications via truncated MessagePack fixext data. The ext/time decoder's ReadSize1 path reads the second byte without first confirming that the input contains at least two bytes, so a lone 0xd4-0xd8 format byte triggers a Go index-out-of-range panic. Exposure requires an application to decode attacker-controlled MessagePack data; the consequence is termination of that process, not data access or modification.
The record
- CVE
- CVE-2026-32284
- Published
- Mar 26, 2026
- Updated
- Mar 26, 2026
- Vendor
- shamaton
- Product
- msgpack
- Classifications
- CWE-125, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 26, 2026CVE publishedPublication date reported by the CVE source.
- Mar 26, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Public exploit references
- Single-byte 0xd6 fixext crasherproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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