CVE-2026-119197: pyasn1 is a generic ASN.1 library for Python
Affects pyasn1Source GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 0.6.5 : patch pyasn1 soon.
Data as of 5 Nov 2026, 12:35 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 7.5 |
|---|
- Patch
- Available – fixed in 0.6.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 29 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10pyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 20.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=esm-infra/focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 18.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=esm-infra/bionicOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
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.
References
- ubuntu.com/security/CVE-2026-119197 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-119197 (opens in a new tab)
- github.com/pyasn1/pyasn1/commit/ce3ec3390784780a530047e0e77be5ff457636a4 (opens in a new tab)
- github.com/pyasn1/pyasn1/pull/132 (opens in a new tab)
- github.com/pyasn1/pyasn1/releases/tag/v0.6.5 (opens in a new tab)
- github.com/pyasn1/pyasn1/security/advisories/GHSA-mm57-4v3p-rchx (opens in a new tab)