CVE Catalog

CVE-2026-96596

MediumCVSS 5.9
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.18%

7th percentile - higher than 7% of all known CVEs

Summary

An infinite loop vulnerability in the erl_tar module (Erlang OTP stdlib) and in copies of that code shipped by hex_core, Hex, and rebar3. An attacker can supply a crafted tar archive with a GNU sparse member whose sparse map ends before its real size, causing the extracting process to loop forever and keep one scheduler busy. The {max_size, N} option only prevents this when N is below the member's real size; extraction with the memory option is not affected.

Risk Assessment

An attacker can cause a denial of service (DoS) by supplying a small crafted tar archive that permanently occupies a process and a scheduler thread until killed. This affects applications using Erlang OTP 29.0 through 29.1.1, rebar3 from 3.27.1, hex 2.4.2 through 2.5.2, and hex_core 0.14.0 through 0.20.0, including on OTP 28 if archives are extracted through affected versions of these libraries.

Recommendation

Upgrade Erlang OTP to 29.1.2 or later (stdlib 8.1.1+), rebar3 to a version newer than 3.27.1, hex to 2.5.3 or later, and hex_core to 0.20.1 or later. If upgrading is not possible, avoid extracting untrusted tar archives or use the {max_size, N} option with a value smaller than the real size of members.

Related vulnerabilities

Original NVD description (English source)

Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in Erlang OTP stdlib (erl_tar module), hexpm hex_core (hex_erl_tar module), hexpm hex (mix_hex_erl_tar module) and erlang rebar3 (r3_hex_erl_tar module) allows an attacker who supplies a tar archive to cause a denial of service via a crafted GNU sparse member. When erl_tar:extract/1,2 writes a member to disk, erl_tar:stream_to_file_loop/3 reads it in chunks of 65536 bytes by default. For a GNU sparse member whose sparse map ends before its real size, erl_tar:do_sparse_read/3 matches its trailing-hole clause before its zero-length clause. After the chunk is used up, the trailing-hole clause reads zero bytes, does not advance the position, and recurses forever. A 2048-byte archive keeps the extracting process and one scheduler busy until the process is killed. The {max_size, N} option prevents this only when N is below the real size of the member. Extraction with the memory option is not affected. hex_core ships its own copy of erl_tar as hex_erl_tar, and Hex and rebar3 ship hex_core with prefixed module names (mix_hex_erl_tar and r3_hex_erl_tar). These copies contain the same code and do not call stdlib's erl_tar, so they are affected on any OTP version. OTP 28 is not affected, but an application running on OTP 28 is affected if it extracts archives through an affected version of hex_core, Hex or rebar3. This issue affects OTP from OTP 29.0 before OTP 29.1.2, corresponding to stdlib from 8.0 before 8.1.1, and rebar3 from 3.27.1 onward, and hex from 2.4.2 before 2.5.3; hex_core: from 0.14.0 before 0.20.1.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS