CPANSec Discloses Seven JSON::XS Flaws Fixed in 4.05
Tech GuruQuick Answer
Upgrade affected JSON::XS deployments to 4.05 or later. Validate incremental parsing, malformed-input recovery and tagged-object handling before restarting dependent services.
Confirm Scope And Apply The Supported Remediation
What to do now: Locate JSON::XS installations in application environments, containers and worker processes; identify service owners and input trust boundaries. Match each advisory to the enabled parser or encoder path. Existing max_size and max_depth settings do not establish protection against the documented bypasses. Install the supported fixed package, rebuild affected deployment artifacts and restart long-lived consumers under the approved maintenance process. Verify the module loaded by each service and test valid traffic, rejected documents and sustained error handling in staging. Retain versions, configuration and memory-behavior results.
Last verified: 2026-11-14 UTC. Recheck the authoritative advisory and supported distribution channel before changing production.
Scope And Authority
| Product scope | JSON::XS Perl JSON parsing and encoding library |
|---|---|
| Advisory | CVE-2026-124536 / CVE-2026-124539 / CVE-2026-124540 / CVE-2026-124541 / CVE-2026-129113 / CVE-2026-129114 / CVE-2026-129115 |
| CVEs | CVE-2026-124536, CVE-2026-124539, CVE-2026-124540, CVE-2026-124541, CVE-2026-129113, CVE-2026-129114, CVE-2026-129115 |
| Authoritative release date | 2026-11-14 11:55 UTC — first CPANSec announcement in the seven-advisory batch; remaining announcements followed through 11:59 UTC. Times are published to minute precision. Software fix released 2026-11-13. |
| Authority revision date | No separate advisory revision date is supplied. |
| Affected versions | JSON::XS before 4.05. CVE-2026-129113 starts at 4.0_00, CVE-2026-129114 at 3.04 and CVE-2026-129115 at 3.0. The other four advisories cover versions before 4.05. Applicability depends on incremental parsing, malformed-input handling or allow_tags/FREEZE use. |
| Fixed version | JSON-XS 4.05 or later |
| CVSS base score | Not provided by the authority |
| CVSS severity | Not provided by the authority |
| Exploitation status | The CPANSec announcements do not confirm exploitation in the wild.; no exploitation claim is inferred. |
What Changed
CPANSec issued seven advisories on November 14 for memory exhaustion, stack exhaustion, buffer errors and use-after-free. The project had released the correcting 4.05 package on November 13; this notice records the new security disclosures.
What To Validate Now
- Inventory. Locate JSON::XS installations in application environments, containers and worker processes; identify service owners and input trust boundaries.
- Establish applicability. Match each advisory to the enabled parser or encoder path. Existing max_size and max_depth settings do not establish protection against the documented bypasses.
- Remediate. Install the supported fixed package, rebuild affected deployment artifacts and restart long-lived consumers under the approved maintenance process.
- Validate. Verify the module loaded by each service and test valid traffic, rejected documents and sustained error handling in staging. Retain versions, configuration and memory-behavior results.
- Retain evidence. Preserve asset and owner identifiers, the applicability decision, before-and-after versions, change approval, installation output, validation results, and any exception or rollback record.
Operational Cautions
The corrected software predates these announcements. Do not describe all seven flaws as remotely exploitable in every application. Check dependency compatibility and recovery behavior before rollout.
Evidence To Retain
- Exact product, release stream, package or application version, enabled feature, environment, and accountable owner.
- UTC timestamps, authority revision, approved change record, installer or package-manager output, and resulting version.
- Relevant logs and monitoring evidence, test results, exceptions, compensating controls, and rollback decisions.
Related TechGeeks Resources
Authoritative References
- CVE-2026-124536 — CPANSec advisory
- CVE-2026-124539 — CPANSec advisory
- CVE-2026-124540 — CPANSec advisory
- CVE-2026-124541 — CPANSec advisory
- CVE-2026-129113 — CPANSec advisory
- CVE-2026-129114 — CPANSec advisory
- CVE-2026-129115 — CPANSec advisory
- Project 4.05 release changes
Correction policy: If the authority changes affected versions, fixed versions, severity, exploitation information, mitigations, or required action, TechGeeks will update this notice and its verification date.
