Service interruption via unbounded RELATIVE-OID decoding
Published Jan 16, 2026 · Updated Aug 27, 2026
Memory exhaustion in pyasn1 before 0.6.2 allows remote attackers to interrupt services by submitting a malformed RELATIVE-OID value. The BER decoder repeatedly left-shifts and accumulates an arbitrary-length arc integer without limiting continuation octets, causing excessive allocation. Exploitation requires an application to decode attacker-controlled ASN.1 data, such as a supplied certificate, and can hang the process or stop its service.
Summary
What happened
Memory exhaustion in pyasn1 before 0.6.2 allows remote attackers to interrupt services by submitting a malformed RELATIVE-OID value. The BER decoder repeatedly left-shifts and accumulates an arbitrary-length arc integer without limiting continuation octets, causing excessive allocation. Exploitation requires an application to decode attacker-controlled ASN.1 data, such as a supplied certificate, and can hang the process or stop its service.
The record
- CVE
- CVE-2026-23490
- Published
- Jan 16, 2026
- Updated
- Aug 27, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Quay
- Classifications
- CWE-770, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 16, 2026CVE publishedPublication date reported by the CVE source.
- Aug 27, 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.
Weakness, pattern, technique
Public exploit references
- Malformed RELATIVE-OID memory-exhaustion proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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