Bug 2483685 (CVE-2026-8796)

Summary: CVE-2026-8796 perl-Sereal-Decoder: Sereal::Decoder: Information disclosure via heap out-of-bounds read with crafted input
Product: [Other] Security Response Reporter: Sandipan Roy <saroy>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in Sereal::Decoder for Perl. A remote attacker could exploit a heap out-of-bounds read vulnerability by providing crafted input containing a specific COPY tag. This tag, when re-decoded, can lead to the consumption of up to 31 bytes from the heap, potentially disclosing sensitive information such as class names or hash keys.
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 2483857, 2483858    
Bug Blocks:    

Description Sandipan Roy 2026-06-01 06:08:50 UTC 
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).