Hi,

The following vulnerability was published for rebar3.

CVE-2026-105274[0]:
| Improper Handling of Highly Compressed Data (Data Amplification)
| vulnerability in hexpm hex_core allows an untrusted repository
| mirror, or a server answering hex_core's API requests, to exhaust
| the memory of the Erlang VM running hex_core. The same code is
| vendored in Hex (mix_hex_repo, mix_hex_api) and rebar3 (r3_hex_repo,
| r3_hex_api).  hex_repo:get_names/1, hex_repo:get_versions/1,
| hex_repo:get_package/2 and hex_repo:get_policy/2 decompress the
| registry response with zlib:gunzip/1 and decode the signed envelope
| before verifying its signature. A mirror doesn't have the
| repository's private key, but it chooses the compressed bytes, so a
| small response decompresses into an envelope of any size before the
| signature check rejects it.  hex_api decodes responses with the
| application/vnd.hex+erlang content type through
| hex_safe_binary_to_term:safe_binary_to_term/1, which calls
| binary_to_term(Binary, [safe]). The safe option prevents atom
| creation, but it accepts compressed terms and doesn't limit the size
| of the decoded term, and the check that rejects functions and ports
| runs after the term has been built. The fix for CVE-2026-21619 added
| the safe option and that check without bounding the decoded size.
| This issue affects rebar3: from 3.9.1 before 3.27.3; hex: from 2.1.0
| before 2.5.2; hex_core: from 0.1.0 before 0.20.0.

https://github.com/hexpm/hex_core/security/advisories/GHSA-7c4r-cgf9-9jmq
https://cna.erlef.org/cves/CVE-2026-105274.html
https://osv.dev/vulnerability/EEF-CVE-2026-105274

Fixed by: https://github.com/erlang/rebar3/commit/360838a22f5b3a88c0358207f2923059bcbb3afb (3.27.3)

If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-105274
https://www.cve.org/CVERecord?id=CVE-2026-105274

Please adjust the affected versions in the BTS as needed.

We believe that the bug you reported is fixed in the latest version of
rebar3, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1150901@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Sergei Golovan <sgolovan@debian.org> (supplier of updated rebar3 package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Sat, 17 Oct 2026 18:21:25 +0300
Source: rebar3
Architecture: source
Version: 3.27.3-1
Distribution: unstable
Urgency: medium
Maintainer: Debian Erlang Packagers <pkg-erlang-devel@lists.alioth.debian.org>
Changed-By: Sergei Golovan <sgolovan@debian.org>
Closes: 1150901
Changes:
 rebar3 (3.27.3-1) unstable; urgency=medium
 .
   * Team upload
 .
   [ Sergei Golovan ]
   * New upstream release.
     - Fix CVE-2026-105274: Improper Handling of Highly Compressed Data
     (Data Amplification) vulnerability in hexpm hex_core vendored in rebar3
     allows an untrusted repository mirror, or a server answering hex_core's
     API requests, to exhaust the memory of the Erlang VM running hex_core.
     Closes: #1150901.
   * Remove patches which port rebar3 to Erlang 29 because they are no longer
     necessary.
   * Bump debhelper compatibility level to 14.
 .
   [ Philipp Huebner ]
   * Remove the priority and rules-require-root fields from debian/control.
Checksums-Sha1:
 9c1c5c434327bb332ba329295dbfda0b19d44539 2095 rebar3_3.27.3-1.dsc
 42d6b9960a91c31148bf7081069cc653b3f7408c 904757 rebar3_3.27.3.orig.tar.gz
 cccf5fa62658777aa097aef6faaeffe6614978e1 7624 rebar3_3.27.3-1.debian.tar.xz
 f8c5d9fecfd5dfa0cd3a02b47a26ec24b25c87ae 14213 rebar3_3.27.3-1_amd64.buildinfo
Checksums-Sha256:
 ae68c380e4f7cfa61d072b5b65e6ea4b09d61c76a42043d20b8b153ed744b0dd 2095 rebar3_3.27.3-1.dsc
 2cf3a0d9a37ad9715fdb870b161ff61282048588ddb424362dacc22444c2d1f8 904757 rebar3_3.27.3.orig.tar.gz
 86eb75aff7180e1cc4cf888912c7b350d30fc28fd33c242ecd6509244e5dc70b 7624 rebar3_3.27.3-1.debian.tar.xz
 0ca29f7290dea47465b871dc9a1bf7e6ebe97688f418162b8e046846b22379b6 14213 rebar3_3.27.3-1_amd64.buildinfo
Files:
 8e31624e5ddf1960b5bdd9852a56f80c 2095 devel optional rebar3_3.27.3-1.dsc
 e09fd9c7242ecb01891d8ac56349f488 904757 devel optional rebar3_3.27.3.orig.tar.gz
 7b82b37850563961509e2669dcefc991 7624 devel optional rebar3_3.27.3-1.debian.tar.xz
 cb80fa4baefe03a3e365453e97258789 14213 devel optional rebar3_3.27.3-1_amd64.buildinfo
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