CVE-2025-15661
Publication date 18 June 2026
Last updated 30 June 2026
Ubuntu priority
Description
libssh2 through 1.11.1, fixed in commit 2dae302, contains an out-of-bounds heap read vulnerability in the sftp_symlink() function in src/sftp.c that allows a malicious SSH server or man-in-the-middle attacker to disclose heap memory contents or cause a crash by sending a crafted SSH_FXP_NAME response. Attackers can supply a link_len value larger than the actual packet data in SSH_FXP_NAME responses for SFTP READLINK and REALPATH operations, triggering a heap buffer over-read of up to target_len minus one bytes due to the missing validation of available packet buffer size before the memcpy operation.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| libssh2 | 26.04 LTS resolute |
Fixed 1.11.1-1ubuntu0.26.04.2
|
| 25.10 questing |
Fixed 1.11.1-1ubuntu0.25.10.2
|
|
| 24.04 LTS noble |
Fixed 1.11.0-4.1ubuntu0.24.04.2
|
|
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 14.04 LTS trusty |
Needs evaluation
|
Severity score breakdown
CVSS version:
Base score
8.3 · High
Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
Base score
6.5 · Medium
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:H
References
Related Ubuntu Security Notices (USN)
- USN-8486-1
- libssh2 vulnerabilities
- 30 June 2026