webpack-dev-middleware vulnerable to Path Traversal via non-slash-terminated publicPath

[ Why it matters ]Priority signals

• Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

zlib 1.2.11 through 1.3.2 contains a heap buffer overflow: after an underlying write() fails, gz_write() returns without resetting strm.next_in, leaving it pointed at the caller's buffer. A later gz* write call then derives a position from the stale pointer and writes past a heap allocation; any write() failure reaches it, including EPIPE on a blocking descriptor, and in versions before 1.3.1.2 the failed write must be followed by a gzclearerr() call.

[ Fixes ]Fixes and patches

• webpack-dev-middleware 8.3.0Fixed version · GitHub Advisories · npm package webpack-dev-middleware: upgrade to 8.3.0 or later (affected >= 8.0.0, < 8.3.0)
• webpack-dev-middleware 7.4.6Fixed version · GitHub Advisories · npm package webpack-dev-middleware: upgrade to 7.4.6 or later (affected < 7.4.5)

[ Packages ]Affected open-source packages

• webpack-dev-middleware npmAffected >= 8.0.0, < 8.3.0 · fixed in 8.3.0 · GHSA-g84c-rxfj-3j2c
• webpack-dev-middleware npmAffected < 7.4.5 · fixed in 7.4.6 · GHSA-g84c-rxfj-3j2c

[ References ]References

• gist.github.com/thesmartshadow/e0b9481792afb7c31e86fee1ff084490technical-descriptionexploit
• github.com/madler/zlib/commit/df84af25dc1942490e1d1c899a07619152a46148patch
• github.com/madler/zlib/blob/v1.3.2/gzwrite.ctechnical-description
• github.com/madler/zlibproduct
• www.vulncheck.com/advisories/zlib-1.3.1.2-through-1.3.2-heap-buffer-overflow-via-gz-vacatethird-party-advisory