CVE-2025-21734: linux Out-of-bounds Write
Vulnerability summary
CVE-2025-21734 is a high (CVSS 7.8) Out-of-bounds Write vulnerability in linux. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 9.9% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 20 · Related 20Timeline
- 27-02-2025PublishedVulnerability first disclosed.
- 05-08-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: Fix copy buffer page size For non-registered buffer, fastrpc driver copies the buffer and pass it to the remote subsystem. There is a problem with current implementation of page size calculation which is not considering the offset in the calculation. This might lead to passing of improper and out-of-bounds page size which could result in memory issue. Calculate page start and page end using the offset adjusted address instead of absolute address.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- NVDNIST7.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.21%
Chance of exploitation in the next 30 days
Percentile
10%
Versus all other CVEs
30-day change
+0.01 pp
From 0.20% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu133 products
- linuxAll versions (No fix recorded) | < 6.8.0-64.67
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 6.8.0-1032.34
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ 02b45b47fbe84e23699bb6bdc74d4c2780e282b4, < c56ba3ea8e3c9a69a992aad18f7a65e43e51d623 | ≥ 02b45b47fbe84e23699bb6bdc74d4c2780e282b4, < c0464bad0e85fcd5d47e4297d1e410097c979e55 | ≥ 02b45b47fbe84e23699bb6bdc74d4c2780e282b4, < 24a79c6bc8de763f7c50f4f84f8b0c183bc25a51 | ≥ 02b45b47fbe84e23699bb6bdc74d4c2780e282b4, < c3f7161123fcbdc64e90119ccce292d8b66281c4 | ≥ 02b45b47fbe84e23699bb6bdc74d4c2780e282b4, < e966eae72762ecfdbdb82627e2cda48845b9dd66 | 5.2
- linux_kernel≥ 5.2, < 6.1.129 | ≥ 6.2, < 6.6.78 | ≥ 6.7, < 6.12.14 | ≥ 6.13, < 6.13.3
Debian1 product
- linux< 6.1.129-1 | < 6.12.15-1
3 vendors · 136 products
