CVE-2026-44660: Pandas · UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+
Affects pandasSource GCVE Database
Not known to be exploited · CVSS 7.5 High · fixed in 5.12.1 : patch pandas soon.
Data as of 9 Nov 2026, 14:18 UTC
- Patch
- Available – fixed in 5.12.1
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 27 May 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10pandaspkg:deb/ubuntu/pandas?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10ujsonpkg:deb/ubuntu/ujson?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSujsonpkg:deb/ubuntu/ujson?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10pandaspkg:deb/ubuntu/pandas?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10ujsonpkg:deb/ubuntu/ujson?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu Pro 24.04 LTSujsonpkg:deb/ubuntu/ujson?arch=source&distro=esm-apps/nobleOther 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
Upgrade UltraJSON (ujson) to version 5.12.1 or later, where this memory leak issue is fixed. No other mitigation is required as the fix addresses the root cause.
Description
UltraJSON (ujson), a fast JSON encoder and decoder used with Python 3.7+, has a memory leak vulnerability in versions prior to 5.12.1. When ujson.dump() writes to a file-like object and the write operation fails with an exception, the serialized JSON string object is not properly decremented, causing memory to leak equal to the size of the payload. This issue is fixed in version 5.12.1.
References
- ubuntu.com/security/CVE-2026-44660 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-44660 (opens in a new tab)
- github.com/ultrajson/ultrajson/commit/82af1d0ac01d09aa40c887b460d44b9d9f4bccd9 (opens in a new tab)
- github.com/ultrajson/ultrajson/releases/tag/5.12.1 (opens in a new tab)
- github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xg (opens in a new tab)