libde265 is an open source implementation of the h.265 video codec. Prior to version 1.0.19, `decoder_context::decode_slice_unit_tiles` (libde265/decctx.cc:920) reads `pps.CtbAddrRStoTS[ctbAddrRS]` at line 966 where `ctbAddrRS = ctbY * ctbsWidth + ctbX` is computed from PPS-supplied `colBd[]`/`rowBd[]` arrays without validating the result against `CtbAddrRStoTS.size() == sps->PicSizeInCtbsY`. A malformed PPS that passes `set_derived_values` but encodes geometry inconsistent with the SPS produces a `ctbAddrRS` past the allocation, causing a 4-byte heap-buffer-overflow READ. Version 1.0.19 fixes the issue.
https://github.com/strukturag/libde265/security/advisories/GHSA-hwhx-x2mq-ccr9
Published: 2026-07-21
Updated: 2026-07-23
Base Score: 6.8
Vector: CVSS2#AV:N/AC:M/Au:N/C:P/I:P/A:P
Severity: Medium
Base Score: 7.8
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Severity: High
Base Score: 6.9
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Severity: Medium
EPSS: 0.00024