Rebar3: Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in hexpm hex_core allows an
Affects rebar3Source GCVE Database
Mentioned vulnerabilities
Not known to be exploited · CVSS 2.1 Low.
Data as of 28 Oct 2026, 22:31 UTC
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 12 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10erlang-hexpkg:deb/ubuntu/erlang-hex?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10rebar3pkg:deb/ubuntu/rebar3?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSerlang-hexpkg:deb/ubuntu/erlang-hex?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSrebar3pkg:deb/ubuntu/rebar3?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSerlang-hexpkg:deb/ubuntu/erlang-hex?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSrebar3pkg:deb/ubuntu/rebar3?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
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.
References
- ubuntu.com/security/CVE-2026-105274 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-105274 (opens in a new tab)
- github.com/hexpm/hex_core/security/advisories/GHSA-7c4r-cgf9-9jmq (opens in a new tab)
- cna.erlef.org/cves/CVE-2026-105274.html (opens in a new tab)
- osv.dev/vulnerability/EEF-CVE-2026-105274 (opens in a new tab)
- github.com/erlang/rebar3/commit/209c02ec57c2cc3207ee0174c3af3675b8dc8f79 (opens in a new tab)
- github.com/erlang/rebar3/commit/360838a22f5b3a88c0358207f2923059bcbb3afb (opens in a new tab)
- github.com/hexpm/hex/commit/671f695ac548ed01f5828c2a739ecaa942b21007 (opens in a new tab)
- github.com/hexpm/hex/commit/d8b60eee97abb119d525306f048969a217d793a5 (opens in a new tab)
- github.com/hexpm/hex_core/commit/ebe25d110717f6a3addba5232cd4a7dc1c76b628 (opens in a new tab)
- github.com/hexpm/hex_core/commit/fbb6d9de472e5edb8d6fb6b32a91cb266137892e (opens in a new tab)