Out-of-bounds read in busybox
Priority MEDIUM 57CWE-125Published · Updated
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- High
- Impact type
- —
- Confidentiality · integrity · availability
- Low · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.
Summary
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 that
Why it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00623 50th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed busybox (busybox): 1.34.0
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| busybox | busybox | before 1.34.0 | 1.34.0 | Patch available | CNA |
- busybox Vendorbusybox Affected before 1.34.0 Fixed in 1.34.0 Patch available CNA
CPE configurations NVD · 20
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:busybox:busybox:*:*:*:*:*:*:*:* | 1.27.0 – 1.33.1 | Vulnerable | busybox |
| cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | 33 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* | 34 | Vulnerable | Fedoraproject |
| cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h300s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
| cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h500s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
- cpe:2.3:a:busybox:busybox:*:*:*:*:*:*:*:* Versions 1.27.0 – 1.33.1 Vulnerable ·busybox
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
- cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:a:netapp:hci_management_node:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:a:netapp:solidfire:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:o:netapp:h300s_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h300s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
- cpe:2.3:o:netapp:h500s_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h500s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
Show 10 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h700s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
| cpe:2.3:o:netapp:h300e_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h300e:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
| cpe:2.3:o:netapp:h500e_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h500e:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
| cpe:2.3:o:netapp:h700e_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h700e:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
| cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:* | not specified by NVD | Vulnerable | NetApp |
| cpe:2.3:h:netapp:h410s:-:*:*:*:*:*:*:* | not specified by NVD | Running on | NetApp |
- cpe:2.3:o:netapp:h700s_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h700s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
- cpe:2.3:o:netapp:h300e_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h300e:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
- cpe:2.3:o:netapp:h500e_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h500e:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
- cpe:2.3:o:netapp:h700e_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h700e:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
- cpe:2.3:o:netapp:h410s_firmware:-:*:*:*:*:*:*:* Versions not specified by NVD Vulnerable ·NetApp
- cpe:2.3:h:netapp:h410s:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·NetApp
Remediation
- Fix · CNA busybox (busybox) Fixed in 1.34.0
Fixed in the same release
Records fixed by the same vendor advisory or release, as the CNA lists them.
- Advisory ·
busybox — FEDORA-2021-c52c0fe490
14 records Highest priority Priority MEDIUM 2 MEDIUM, 12 LOW
Other records, highest priority first
- TI-2021-18791 An attacker-controlled pointer free in Busybox's hush applet leads to denial of service…Priority MEDIUM 48
- TI-2021-18800 Use after free in busyboxPriority LOW 39
- TI-2021-18799 Use after free in busyboxPriority LOW 39
- Advisory ·
busybox — FEDORA-2021-5a95823596
14 records Highest priority Priority MEDIUM 2 MEDIUM, 12 LOW
Other records, highest priority first
- TI-2021-18791 An attacker-controlled pointer free in Busybox's hush applet leads to denial of service…Priority MEDIUM 48
- TI-2021-18800 Use after free in busyboxPriority LOW 39
- TI-2021-18799 Use after free in busyboxPriority LOW 39
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2021-42374
- 2026-10-03 Alias added: GHSA-6f92-r9cq-v6cq
- 2026-11-05 EPSS moved to the 50th–90th percentile
References
Exploit 1
Advisory 3
More Busybox vulnerabilities
- TI-2016-05394 The recv_and_process_client_pkt function in networking/ntpd.c in busybox allows remote… CVSS 3.1HIGH 7.5
- TI-2018-15900 Busybox contains a Missing SSL certificate validation vulnerability in The "busybox wget"… CVSS 3.1HIGH 8.1
- TI-2018-15917 BusyBox project BusyBox wget version prior to commit… CVSS 3.1CRITICAL 9.8
- TI-2016-01959 Heap-based buffer overflow in the DHCP client (udhcpc) in BusyBox before 1.25.0 allows… CVSS 3.1CRITICAL 9.8
- TI-2025-37846 BusyBox wget thru 1.3.7 accepted raw CR (0x0D)/LF (0x0A) and other C0 control bytes in… CVSS 3.1MEDIUM 6.5
- TI-2023-22583 A use-after-free vulnerability in BusyBox v.1.36.1 allows attackers to cause a denial of… CVSS 3.1MEDIUM 5.5
Sources
- CVE-2021-42374 · CVE Program
- CVE-2021-42374 · NVD
- FIRST EPSS
- GHSA-6f92-r9cq-v6cq · GitHub Advisory Database · CC BY 4.0
- CVE-2021-42374 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences