Creation of Immutable Text Using String Concatenation Affecting python-pyasn1 package, versions *


Severity

Recommended
0.0
high
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.53% (45th percentile)

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  • Snyk IDSNYK-RHEL10-PYTHONPYASN1-22085796
  • published31 Oct 2026
  • disclosed29 Oct 2026

Introduced: 29 Oct 2026

NewCVE-2026-119195  (opens in a new tab)
CWE-1046  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 python-pyasn1.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python-pyasn1 package and not the python-pyasn1 package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

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 Base Scores

version 3.1