CVE-2021-42374
An out-of-bounds heap read in Busybox's unlzma applet leads to information leak and denial of service when crafted LZMA-compressed input is decompressed. This can be triggered by any applet/format
02 Description
An out-of-bounds heap read in Busybox's unlzma applet leads to information leak and denial of service when crafted LZMA-compressed input is decompressed. This can be triggered by any applet/format
03 Exploitation and scoring
- Exploitation
- Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
- SSVC decision
- ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.62% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 49.6% of scored records. A rank, not a probability.
- NVD base score
- 5.3 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-06-17.
- Red Hat severity
- Moderate. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2021-11-15 00:00Z4 YR AGO
- Last updated
- 2025-11-03 20:34Z11 MO AGO
- Reserved
- 2021-10-14
- Assigning CNA
- JFROG
- Record state
- PUBLISHED
- Severity
- Medium (CVSS 5.3)
- CNA CVSS vector
- CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H
- Weaknesses
- CWE-125Out-of-bounds ReadBase
- Data version
- 5.2
- Document digest
- 8a6e023400df49ea4ae15817d5d16987d2645bc961fd3c33bbd0a4e9ba0ef704
05 Affected products
06 References
- jfrog.comhttps://jfrog.com/blog/unboxing-busybox-14-new-vulnerabilities-uncovered-by-claroty-and-jfrog/
- lists.fedoraproject.orgFEDORA-2021-5a95823596https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UQXGOGWBIYWOIVXJVRKHZR34UMEHQBXS/
- lists.fedoraproject.orgFEDORA-2021-c52c0fe490https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6T2TURBYYJGBMQTTN2DSOAIQGP7WCPGV/
- security.netapp.comhttps://security.netapp.com/advisory/ntap-20211223-0002/
- claroty.comhttps://claroty.com/team82/research/unboxing-busybox-14-vulnerabilities-uncovered-by-claroty-jfrog
- lists.debian.orghttps://lists.debian.org/debian-lts-announce/2025/01/msg00012.html
07 Fixed in
Arch Linux
- busybox Fixed in 1.34.1-1
- mkinitcpio-busybox Fixed in 1.34.1-1
Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.
Debian 12
- busybox Fixed in 1:1.35.0-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- busybox Fixed in 1:1.35.0-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- busybox Fixed in 1:1.35.0-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 18.04 LTS
- busybox Fixed in 1:1.27.2-2ubuntu3.4
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 20.04 LTS
- busybox Fixed in 1:1.30.1-4ubuntu6.4
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
Ubuntu 22.04 LTS
- busybox Fixed in 1:1.30.1-7ubuntu2
Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.