CVE-2026-90954

LOWCVSS 7.8 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

Track advisory updates for patch or workaround availability

Recommended action window: Monitor and triage in normal cycle

NVD description

A flaw was found in BusyBox's dpkg-deb archive extraction. The ar archive handler flushes deferred symlinks after each archive member, unlike the tar, cpio, and unzip handlers which flush once after the last member. A specially crafted .deb archive with two data.tar members can exploit this ordering: the first member declares a symlink pointing to an absolute path (e.g., '/'), which is deferred as unsafe but flushed after the first member. The second member declares a regular file whose path traverses the now-live symlink, resulting in a file being written outside the intended extraction directory. This could allow an attacker to write arbitrary files to arbitrary locations when a user extracts a crafted .deb package.

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0.0/ 10 priority

Sources & remediation

Other references

Weakness type (CWE)

CWE-59

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

NONE

Momentum

NONE

Threat summary

1 mentions across 1 observed day

What's happening

1 total mentions across 1 day

Deep dive

Activity timeline1 mentions / 1d

Full discourse1 post

Upwind Security MDR@UpwindMDR1d
🚨High - BusyBox Vulnerabilities dpkg-deb Arbitrary Write (CVE-2026-90954) Extraction mishandles symlinks in data.tar archives, allowing arbitrary file writes outside the target directory. 👉Affected: dpkg-deb builds. Check: "busybox --list | grep dpkg-deb" httpd Request Smuggling (CVE-2026-88829) Mishandled pipelined requests let a smuggled 2nd request bypass proxy path restrictions to reach the backend. 👉Affected: httpd reverse proxy. Mitigate: Remove "P:" lines or use a full proxy (Nginx/HAProxy) in front.
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