CVE-2026-119197: high-severity vulnerability in pyasn1
pyasn1: Quadratic-complexity denial of service in binary REAL decoding
Published · Updated
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.4%
pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.5, binary REAL decoding builds a large mantissa one octet at a time by shifting a growing integer and slicing the remaining byte string. Attacker-controlled ASN.1 includes a binary-encoded REAL with a large mantissa and reaches BER, CER, or DER decode(), with or without a schema containing REAL. RealPayloadDecoder.valueDecoder repeatedly performs a left shift, OR, and suffix copy for every mantissa octet, making decode time quadratic in mantissa length. A comparatively small REAL value can hold a decoding worker on one CPU core for seconds or longer and cause availability loss. This issue is fixed in version 0.6.5.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
pyasn1 · pyasn1Related CVEs — pyasn1
In the same product, most dangerous first.
CVE-2026-30922HIGHpyasn1 Vulnerable to Denial of Service via Unbounded RecursionEPSS 0.8%CVE-2026-23490HIGHpyasn1 has a DoS vulnerability in decoderEPSS 0.8%CVE-2026-59884HIGHpyasn1 BER/CER/DER decoder denial of service via unbounded long-form tag IDsEPSS 0.6%CVE-2026-59885HIGHpyasn1: Quadratic complexity in OBJECT IDENTIFIER and RELATIVE-OID processing allows denial of serviceEPSS 0.6%CVE-2026-119195HIGHpyasn1: Quadratic-time denial of service in constructed string and indefinite-length ANY decodingEPSS 0.5%CVE-2026-59886HIGHpyasn1: Uncontrolled resource consumption when converting decoded REAL valuesEPSS 0.4%