CVE-2026-4177: CWE-122 Heap-based Buffer Overflow in TODDR YAML::Syck
YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities including a high-severity heap buffer overflow in the YAML emitter. The heap overflow occurs when class names exceed the initial 512-byte allocation. The base64 decoder could read past the buffer end on trailing newlines. strtok mutated n->type_id in place, corrupting shared node data. A memory leak occurred in syck_hdlr_add_anchor when a node already had an anchor. The incoming anchor string 'a' was leaked on early return.
AI Analysis
Technical Summary
YAML::Syck versions through 1.36 for Perl contain multiple security vulnerabilities, including a high-severity heap buffer overflow triggered when class names exceed a 512-byte buffer allocation in the YAML emitter. Other vulnerabilities include a base64 decoder that can read beyond buffer boundaries on trailing newlines, in-place mutation of node type IDs corrupting shared data, and a memory leak in the anchor handling function when duplicate anchors are added. These issues collectively pose risks of memory corruption and resource leaks. The vulnerabilities are tracked under CVE-2026-4177 with a CVSS 3.1 score of 9.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H).
Potential Impact
The heap buffer overflow can lead to memory corruption, potentially causing application crashes or denial of service. The base64 decoder flaw risks reading out-of-bounds memory, which may lead to crashes or data leakage. Corruption of shared node data can destabilize application behavior. The memory leak may cause resource exhaustion over time. The CVSS score of 9.1 reflects critical impact on confidentiality and availability, with no privileges or user interaction required for exploitation.
Mitigation Recommendations
Red Hat has released security updates addressing CVE-2026-4177 in perl-YAML-Syck packages for Red Hat Enterprise Linux 7 Extended Lifecycle Support. Users should apply these official patches promptly to remediate the vulnerabilities. Refer to Red Hat advisories RHSA-2026:8311 and RHSA-2026:6470 for update instructions. Patch status is confirmed with official fixes available. No additional mitigations are indicated beyond applying the vendor-provided updates.
CVE-2026-4177: CWE-122 Heap-based Buffer Overflow in TODDR YAML::Syck
Description
YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities including a high-severity heap buffer overflow in the YAML emitter. The heap overflow occurs when class names exceed the initial 512-byte allocation. The base64 decoder could read past the buffer end on trailing newlines. strtok mutated n->type_id in place, corrupting shared node data. A memory leak occurred in syck_hdlr_add_anchor when a node already had an anchor. The incoming anchor string 'a' was leaked on early return.
CVSS v3.1
Score 9.1critical
Affected software
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
YAML::Syck versions through 1.36 for Perl contain multiple security vulnerabilities, including a high-severity heap buffer overflow triggered when class names exceed a 512-byte buffer allocation in the YAML emitter. Other vulnerabilities include a base64 decoder that can read beyond buffer boundaries on trailing newlines, in-place mutation of node type IDs corrupting shared data, and a memory leak in the anchor handling function when duplicate anchors are added. These issues collectively pose risks of memory corruption and resource leaks. The vulnerabilities are tracked under CVE-2026-4177 with a CVSS 3.1 score of 9.1 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H).
Potential Impact
The heap buffer overflow can lead to memory corruption, potentially causing application crashes or denial of service. The base64 decoder flaw risks reading out-of-bounds memory, which may lead to crashes or data leakage. Corruption of shared node data can destabilize application behavior. The memory leak may cause resource exhaustion over time. The CVSS score of 9.1 reflects critical impact on confidentiality and availability, with no privileges or user interaction required for exploitation.
Mitigation Recommendations
Red Hat has released security updates addressing CVE-2026-4177 in perl-YAML-Syck packages for Red Hat Enterprise Linux 7 Extended Lifecycle Support. Users should apply these official patches promptly to remediate the vulnerabilities. Refer to Red Hat advisories RHSA-2026:8311 and RHSA-2026:6470 for update instructions. Patch status is confirmed with official fixes available. No additional mitigations are indicated beyond applying the vendor-provided updates.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- CPANSec
- Date Reserved
- 2026-03-14T19:36:56.710Z
- Cvss Version
- null
- State
- PUBLISHED
- Vendor Advisory Urls
- [{"url":"https://access.redhat.com/security/cve/CVE-2026-4177","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:8311","vendor":"Red Hat"},{"url":"https://access.redhat.com/errata/RHSA-2026:6470","vendor":"Red Hat"}]
Threat ID: 69b96182771bdb1749b5a612
Added to database: 03/17/2026, 14:13:22 UTC
Last enriched: 07/15/2026, 09:24:59 UTC
Last updated: 07/31/2026, 19:22:59 UTC
Views: 183
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