CVE-2026-57077
Description
A flaw was found in YAML::Syck. An out-of-bounds read vulnerability exists due to an unbounded newline scan during block-scalar lexing. A remote attacker could exploit this by providing a specially crafted YAML document, leading to potential information disclosure. This issue is an incomplete fix for a previously identified vulnerability.
Statement
Moderate: An out-of-bounds read flaw in perl-YAML-Syck can lead to information disclosure when processing specially crafted YAML documents. This vulnerability, an incomplete fix for CVE-2025-11683, occurs during block-scalar lexing if an application loads untrusted YAML input containing a block scalar at a document boundary.
Mitigation
To mitigate this vulnerability, restrict applications using `perl-YAML-Syck` from processing untrusted YAML documents. Ensure that only trusted input sources are parsed by `YAML::Syck`. If `perl-YAML-Syck` is not required, consider removing the package to eliminate the exposure, noting that this may affect dependent applications.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 4.3 | N/A | 7.7 |
| Attack Vector | Network | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | Low | N/A | High |
| Integrity Impact | None | N/A | None |
| Availability Impact | None | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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