CVE-2026-77117
Description
A flaw was found in glibc. A remote attacker could exploit this vulnerability by providing specially crafted input during SHIFT_JISX0213 to UCS-4 text conversion. This crafted input can cause the application to repeatedly emit a buffered code point without consuming further input, leading to persistent retry churn. This can result in a denial of service (DoS) for callers converting untrusted text.
Statement
This Moderate impact flaw in glibc's SHIFT_JISX0213 to UCS-4 conversion can lead to a denial of service. Exploitation requires an attacker to provide specially crafted input that an application converts using this specific path, triggering a 2-byte sequence and a caller that retries after an E2BIG error with insufficient output space. Red Hat products are only affected if they utilize this uncommon conversion path and exhibit the described retry behavior.
Mitigation
Do not convert untrusted input using the SHIFT_JISX0213 character set (for example via iconv). Where conversion cannot be avoided, apply process CPU time limits and container cgroup resource limits so a hung converter cannot exhaust host resources.
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).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.9 | N/A | 5.9 |
| Attack Vector | Network | N/A | Network |
| Attack Complexity | High | N/A | High |
| Privileges Required | None | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
cve.org: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (CPU); DoS: Resource Consumption (Memory); DoS: Amplification
An infinite loop will cause unexpected consumption of resources, such as CPU cycles or memory. The software's operation may slow down, or cause a long time to respond.
Acknowledgements
This issue was discovered by Found by AISLE in partnership with Red Hat (Aisle Research).
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