CVE-2026-8796
Description
Sereal::Decoder versions before 5.005 for Perl allow heap out-of-bounds read via crafted input. In Perl/Decoder/srl_decoder.c, srl_read_object() and srl_read_hash() process a COPY tag, a back-reference whose target byte the decoder re-decodes as a fresh tag. When that target byte matches the SHORT_BINARY pattern (an inline string whose length is encoded in the low bits of the tag), the resulting read is not bounded to precede the COPY tag's own offset and can run past the end of the input buffer. An attacker controlled COPY offset can land inside a previously decoded value rather than on a tag boundary, planting a byte that the decoder reads as a SHORT_BINARY tag and consuming up to 31 following bytes from the heap as a class name (OBJECT path) or hash key (HASH path).
Predictions
Heuristic predictions, AS-IS, for prioritization only.
Mitigations
Mitigation details
CVE-2026-8796 NameCVE-2026-8796 DescriptionSereal::Decoder versions before 5.005 for Perl allow heap out-of-bounds read via crafted input. In Perl/Decoder/srl_decoder.c, srl_read_object() and srl_read_hash() process a COPY tag, a back-reference whose target byte the decoder re-decodes as a fresh tag. When that target byte matches the SHORT_BINARY pattern (an inline string whose length is encoded…
CVE-2026-8796
| Name | CVE-2026-8796 |
| Description | Sereal::Decoder versions before 5.005 for Perl allow heap out-of-bounds read via crafted input. In Perl/Decoder/srl_decoder.c, srl_read_object() and srl_read_hash() process a COPY tag, a back-reference whose target byte the decoder re-decodes as a fresh tag. When that target byte matches the SHORT_BINARY pattern (an inline string whose length is encoded in the low bits of the tag), the resulting read is not bounded to precede the COPY tag's own offset and can run past the end of the input buffer. An attacker controlled COPY offset can land inside a previously decoded value rather than on a tag boundary, planting a byte that the decoder reads as a SHORT_BINARY tag and consuming up to 31 following bytes from the heap as a class name (OBJECT path) or hash key (HASH path). |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
| Debian Bugs | 1138633 |
Vulnerable and fixed packages
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| libsereal-decoder-perl (PTS) | bullseye | 4.018+ds-1 | vulnerable |
| bookworm | 5.003+ds-1 | vulnerable | |
| forky, trixie | 5.004+ds-1 | vulnerable | |
| sid | 5.006+ds-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| libsereal-decoder-perl | source | (unstable) | 5.006+ds-1 | 1138633 |
Notes
[trixie] - libsereal-decoder-perl <no-dsa> (Minor issue)
[bookworm] - libsereal-decoder-perl <no-dsa> (Minor issue)
https://lists.security.metacpan.org/cve-announce/msg/40571630/
Fixed by: https://github.com/Sereal/Sereal/commit/303a2c69cdba80bf37a3ff43461e0aa78198a7a3 (Sereal-5.005)
Apply commands
[trixie] - libsereal-decoder-perl <no-dsa> (Minor issue)[bookworm] - libsereal-decoder-perl <no-dsa> (Minor issue)https://lists.security.metacpan.org/cve-announce/msg/40571630/Fixed by: https://github.com/Sereal/Sereal/commit/303a2c69cdba80bf37a3ff43461e0aa78198a7a3 (Sereal-5.005)OS impact
Debian Mixed 5 releases
| Version | Status | Fixed in |
|---|---|---|
| trixie | Affected | — |
| sid | Fixed | 5.006+ds-1 |
| forky | Affected | — |
| bullseye | Affected | — |
| bookworm | Affected | — |
References
CWEs
CWE-125
Community-verified mitigations for this CVE will appear above when contributors publish them.
Verify integrity in audit chain (admin only). AS-IS.