CVE-2026-59886: pyasn1 is a generic ASN.1 library for Python
Affects pyasn1Source GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 0.4.8-1ubuntu0.3 : patch pyasn1 soon.
Data as of 10 Nov 2026, 06:10 UTC
- Patch
- Available – fixed in 0.4.8-1ubuntu0.3, 0.4.8-4ubuntu0.3, 0.6.3-1ubuntu0.1
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 14 Jul 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 9 Nov 2026.
What to do
Upgrade the Ubuntu pyasn1 to 0.4.8-1ubuntu0.3 (package) or 0.4.8-4ubuntu0.3 (package) or 0.6.3-1ubuntu0.1 (package).
Patches and advisories
Affected software
| Product | 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– |
Ubuntu Pro 16.04 LTSpyasn1pkg:deb/ubuntu/pyasn1?arch=source&distro=esm-infra-legacy/xenialOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
This vulnerability is fixed in pyasn1 version 0.6.4 and later. Ubuntu users should update to the fixed package versions: 0.4.8-1ubuntu0.3, 0.4.8-4ubuntu0.3, or 0.6.3-1ubuntu0.1 depending on their Ubuntu release. Applying standard system updates will install these fixes. No additional mitigation is required once patched.
Description
pyasn1 versions prior to 0.6.4 contain a vulnerability in the univ.Real type where conversion of decoded REAL values to Python float types can consume excessive CPU and memory. This occurs because a BER, CER, or DER encoded REAL value with a very large exponent triggers expensive big-integer exponentiation during float conversion operations, potentially causing application hangs. The issue is fixed in version 0.6.4.
References
- ubuntu.com/security/CVE-2026-59886 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-59886 (opens in a new tab)
- github.com/pyasn1/pyasn1/security/advisories/GHSA-hm4w-wwcw-mr6r (opens in a new tab)
- github.com/pyasn1/pyasn1/releases/tag/v0.6.4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8712-1 (opens in a new tab)