Answer in brief
CVE-2026-129114 records a Unknown severity vulnerability in JSON::XS versions from 3.04 before 4.05 for Perl write one byte past a heap buffer when appending a one-byte chunk in incr_parse. The current sources do not mark it as known exploited. The current feed maps JSON-XS (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps JSON-XS (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| JSON-XSgeneric | >=3.04 <4.05 | 4.05 |
Published upstream
Nov 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 14, 2026
JSON::XS versions from 3.04 before 4.05 for Perl write one byte past a heap buffer when appending a one-byte chunk in incr_parse. The incremental buffer grows to one and a half times the length it must hold, with no room reserved for the terminating NUL. For an empty buffer and a one-byte chunk that request is one byte, which a buffer whose front was removed by earlier decodes can already have, so nothing is reallocated and the NUL lands one byte past the allocation. A peer streaming data to an incr_parse consumer, choosing how the input is split into reads, can cause a one-byte heap out-of-bounds write.
Quoted source text, attributed separately from HOL analysis.