CVE-2026-124541: JSON::XS versions before 4.05 for Perl leak the decoded part of a rejected long string in decode_str
Source GCVE Database
Not known to be exploited : upgrade to 4.05 when convenient.
Data as of 14 Nov 2026, 13:17 UTC
Rated Medium by Threat Radar's AI analysis · CVSS not yet scored by NVD
Thin evidence
One scorer or none- Patch
- Available – fixed in 4.05
Exploitation evidence
Disclosed: evidence found.
CVE published 14 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 14 Nov 2026.
What to do
Upgrade JSON-XS (Perl module) to 4.05.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| JSON-XS | Affected
| Fixed in
|
CPANJSON-XSpkg:cpan/JSON-XSOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in JSON::XS version 4.05 and later. Users should upgrade to version 4.05 or newer to resolve this memory leak issue. No other mitigation is indicated.
Description
JSON::XS versions before 4.05 for Perl contain a vulnerability in the decode_str function where rejected long strings leak decoded data. This occurs because decoded string parts are stored in fixed-size buffers that are not freed upon rejection due to control characters, invalid escapes, malformed UTF-8, or premature end of input. A process that continues running after such failed decodes retains these leaked string parts, potentially exhausting memory over repeated requests.