CVE-2026-53938Public exploitNetwork attack vector

Pre-authentication crash via oversized JWE encrypted key

Published Sep 8, 2026 · Updated Sep 9, 2026

Heap buffer overflow in OpenIDC cjose before 0.6.2.5 allows remote attackers to crash applications via a crafted JWE encrypted key. The _cjose_jwe_decrypt_ek_aes_kw() path passes an unchecked encrypted_key length to AES_unwrap_key(), which writes into a fixed-size CEK heap buffer. Exposure requires an application to decrypt untrusted JWEs with A128KW, A192KW, or A256KW; heap corruption can also cause further memory-corruption impact.

CVSS severity8.2
High
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in OpenIDC cjose before 0.6.2.5 allows remote attackers to crash applications via a crafted JWE encrypted key. The _cjose_jwe_decrypt_ek_aes_kw() path passes an unchecked encrypted_key length to AES_unwrap_key(), which writes into a fixed-size CEK heap buffer. Exposure requires an application to decrypt untrusted JWEs with A128KW, A192KW, or A256KW; heap corruption can also cause further memory-corruption impact.

The record

CVE
CVE-2026-53938
Published
Sep 8, 2026
Updated
Sep 9, 2026
Vendor
OpenIDC
Product
cjose
Classifications
CWE-787, CWE-122, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 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?

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

  1. Affected versionversion=< 0.6.2.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenIDC · cjoseversion=< 0.6.2.5

Published CVSS scores

8.2GitHub Security AdvisoriesCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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.

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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-787Out-of-bounds Write
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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