CVE-2026-95520
Description
A heap-based buffer overflow flaw was found in rpm. Parsing a symlink entry in an untrusted RPM package whose declared RPMTAG_LONGFILESIZES value is 0xFFFFFFFFFFFFFFFF causes an integer overflow in iterReadArchiveNext() that shrinks a buffer allocation to one byte, after which the payload's independently-controlled cpio filesize field is used to write attacker-controlled data past the end of that allocation. This is reachable via rpm2cpio, rpm2archive, and rpm -qlvp on an untrusted package.
Statement
This issue is rated Moderate because, while parsing a crafted RPM triggers an attacker-controlled-length heap write, exploitation is local: a user or automated workflow must choose to run rpm2cpio, rpm2archive, rpm -qlvp, or an install/rebuild against the untrusted package. The flaw is not exposed as a network service, consistent with other Moderate-rated integer-overflow/heap-overflow flaws already tracked against the same iterReadArchiveNext() symlink-handling code path.
Mitigation
To reduce exposure, avoid processing or extracting RPM packages from untrusted sources. Do not use `rpm2cpio`, `rpm2archive`, or `rpm -qlvp` on RPM files whose origin and integrity cannot be verified.
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 | 7.1 | N/A | 7.1 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | None | N/A | None |
| User Interaction | Required | N/A | Required |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | None |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H
Understanding the Weakness (CWE)
Integrity
Technical Impact: Modify Memory; Execute Unauthorized Code or Commands
Write operations could cause memory corruption. In some cases, an adversary can modify control data such as return addresses in order to execute unexpected code.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
Attempting to access out-of-range, invalid, or unauthorized memory could cause the product to crash.
Other
Technical Impact: Unexpected State
Subsequent write operations can produce undefined or unexpected results.
Acknowledgements
Red Hat would like to thank tao pan for reporting this issue.
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