CVE catalog

CVE-2021-45958

ujson: CVE-2021-45958

Severity: Medium · CVSS 5.5CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Published: Jan 1, 2022, 12:15:08 AM UTC
Source: [NVD] · [CVE record]
EPSS: 1.67% · Oct 25, 2026

UltraJSON (aka ujson) through 5.1.0 has a stack-based buffer overflow in Buffer_AppendIndentUnchecked (called from encode). Exploitation can, for example, use a large amount of indentation.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	ujson	sid	`5.13.0-1`	fixed
Debian	ujson	forky	`5.13.0-1`	fixed
Debian	ujson	trixie	`5.10.0-1`	fixed
Debian	ujson	bookworm	`5.7.0-1`	fixed
Ubuntu	ujson	pro	`4.0.2-1`	vulnerable
Ubuntu	ujson	pro	`4.0.2-1build1`	vulnerable
Ubuntu	ujson	pro	`4.2.0-1`	vulnerable
Ubuntu	ujson	pro	`5.1.0-1`	vulnerable
Ubuntu	ujson	pro	`5.1.0-1build1`	vulnerable
Ubuntu	ujson	pro	`5.1.0-1ubuntu0.1~esm1`	fixed
Ubuntu	ujson	20.04	`1.35-3build1`	vulnerable
Ubuntu	ujson	20.04	`1.35-3build2`	vulnerable
Ubuntu	ujson	20.04	`1.35-4`	vulnerable
Ubuntu	ujson	20.04	`1.35-4build1`	vulnerable
Ubuntu	ujson	20.04	`1.35-4ubuntu0.1`	fixed
Opensuse	python-ujson	tumbleweed	`5.10.0-1.5`	fixed
Suse	python-ujson	linux enterprise module for development tools 15 sp4	`1.35-150100.3.8.1`	fixed
Suse	python-ujson	linux enterprise module for package hub 15 sp4	`1.35-150100.3.8.1`	fixed
Suse	python-ujson	linux enterprise real time 15 sp3	`1.35-150100.3.8.1`	fixed
Opensuse	python-ujson	leap 15.4	`1.35-150100.3.8.1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	ujson	source	sid	`5.2.0-1`	not yet assigned	Not reported	[1005140]
Debian	ujson	source	forky	`5.2.0-1`	not yet assigned	Not reported	[1005140]
Debian	ujson	source	trixie	`5.2.0-1`	not yet assigned	Not reported	[1005140]
Debian	ujson	source	bookworm	`5.2.0-1`	not yet assigned	Not reported	[1005140]
Ubuntu	ujson	deb	pro	`5.1.0-1ubuntu0.1~esm1`	Not reported	USN-6629-1	Not reported
Ubuntu	ujson	deb	20.04	`1.35-4ubuntu0.1`	Not reported	USN-6629-2	Not reported
Opensuse	python-ujson	rpm	tumbleweed	`5.10.0-1.5`	Not reported	OPENSUSE-SU-2025:15107-1	Not reported
Suse	python-ujson	rpm	linux enterprise module for development tools 15 sp4	`1.35-150100.3.8.1`	Not reported	SUSE-SU-2023:2134-1	Not reported
Suse	python-ujson	rpm	linux enterprise module for package hub 15 sp4	`1.35-150100.3.8.1`	Not reported	SUSE-SU-2023:2134-1	Not reported
Suse	python-ujson	rpm	linux enterprise real time 15 sp3	`1.35-150100.3.8.1`	Not reported	SUSE-SU-2023:2134-1	Not reported
Opensuse	python-ujson	rpm	leap 15.4	`1.35-150100.3.8.1`	Not reported	SUSE-SU-2023:2134-1	Not reported

[Debian bug #1005140]

OpenFactory catalog packages

[openSUSE Tumbleweed]

[python313-ujson]Unknown
Source package: [python-ujson]
Details (1)
- 5.13.0-1.3 · x86_64 · tumbleweed
  Unknown · Fixed: 5.10.0-1.5
  Version impact unknown
  dsa · python-ujson · opensuse · tumbleweed
[python314-ujson]Unknown
Source package: [python-ujson]
Details (1)
- 5.13.0-1.3 · x86_64 · tumbleweed
  Unknown · Fixed: 5.10.0-1.5
  Version impact unknown
  dsa · python-ujson · opensuse · tumbleweed

[Debian 12 (Bookworm)]

[python3-ujson]Fixed
Source package: [ujson]
Details (2)
- 5.7.0-1 · amd64 · bookworm
  Fixed · Fixed: 5.2.0-1
  dsa · ujson · debian · bookworm; dsa · ujson · debian · 12
- 5.7.0-1 · arm64 · bookworm
  Fixed · Fixed: 5.2.0-1
  dsa · ujson · debian · bookworm; dsa · ujson · debian · 12

[Debian 13 (Trixie)]

[python3-ujson]Fixed
Source package: [ujson]
Details (2)
- 5.10.0-1+b4 · amd64 · trixie
  Fixed · Fixed: 5.2.0-1
  dsa · ujson · debian · 13
- 5.10.0-1+b4 · arm64 · trixie
  Fixed · Fixed: 5.2.0-1
  dsa · ujson · debian · 13

Observed: Oct 23, 2026, 6:04:01 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [SUSE security advisories and VEX]