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).

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Fixes

Solution

Upgrade to Sereal::Decoder 5.005 or later.


Workaround

No workaround given by the vendor.

History

Sun, 31 May 2026 21:30:00 +0000

Type Values Removed Values Added
First Time appeared Yves
Yves sereal::decoder
Vendors & Products Yves
Yves sereal::decoder

Sun, 31 May 2026 20:15:00 +0000

Type Values Removed Values Added
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).
Title Sereal::Decoder versions before 5.005 for Perl allow heap out-of-bounds read via crafted input
Weaknesses CWE-125
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-05-31T19:43:22.054Z

Reserved: 2026-05-18T00:38:16.965Z

Link: CVE-2026-8796

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-05-31T20:16:30.813

Modified: 2026-05-31T20:16:30.813

Link: CVE-2026-8796

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-31T21:30:06Z

Weaknesses