CVE-2026-119195

pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, constructed string and indefinite-length ANY decoding repeatedly concatenates each fragment onto a growing bytes value. Attacker-controlled BER or CER data can use many constructed OCTET STRING or character-string fragments. DER rejects constructed OCTET STRING without a schema, but accepts its definite-length form when asn1Spec selects univ.OctetString; it also accepts constructed character strings such as UTF8String without a schema, even though those encodings are not valid DER. The separate indefinite-length ANY path is reachable in BER and CER when asn1Spec selects univ.Any; DER rejects indefinite lengths. OctetStringPayloadDecoder uses growing header concatenation and AnyPayloadDecoder.indefLenValueDecoder uses growing chunk concatenation, repeatedly copying an increasing prefix and causing quadratic work. A sufficiently fragmented value can occupy decoding workers and cause CPU exhaustion without confidentiality or integrity impact. This issue is fixed in version 0.6.5.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/pyasn1/pyasn1/commit/4ce00797c594b59c1fd6b86d9ebc3ba87b7ec9f9
https://github.com/pyasn1/pyasn1/pull/132
https://github.com/pyasn1/pyasn1/releases/tag/v0.6.5
https://github.com/pyasn1/pyasn1/security/advisories/GHSA-9m75-vc3g-4x39
https://github.com/pyasn1/pyasn1/security/advisories/GHSA-9m75-vc3g-4x39

Configurations

No configuration.

History

29 Oct 2026, 21:17

Type	Values Removed	Values Added
References	~~() https://github.com/pyasn1/pyasn1/security/advisories/GHSA-9m75-vc3g-4x39 -~~	() https://github.com/pyasn1/pyasn1/security/advisories/GHSA-9m75-vc3g-4x39 -

29 Oct 2026, 20:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-10-29 20:17

Updated : 2026-10-30 17:18

NVD link : CVE-2026-119195

Mitre link : CVE-2026-119195

CVE.ORG link : CVE-2026-119195

JSON object : View

Products Affected

No product.

CWE

CWE-407

Inefficient Algorithmic Complexity

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