CVE-2025-39847: Debian Linux

Medium severity, CVSS 5.5. EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: ppp: fix memory leak in pad_compress_skb If alloc_skb() fails in pad_compress_skb(), it returns NULL without releasing the old skb. The caller does: skb = pad_compress_skb(ppp, skb); if (!skb) goto drop; drop: kfree_skb(skb); When pad_compress_skb() returns NULL, the reference to the old skb is lost and kfree_skb(skb) ends up doing nothing, leading to a memory leak. Align pad_compress_skb() semantics with realloc(): only free the old skb if allocation and compression succeed. At the call site, use the new_skb variable so the original skb is not lost when pad_compress_skb() fails.

Affected products

• Debian Debian Linux: version 11.0 only
• Linux Linux Kernel: from 2.6.15, before 5.4.299 (fixed in 5.4.299); from 5.5, before 5.10.243 (fixed in 5.10.243); from 5.11, before 5.15.192 (fixed in 5.15.192); from 5.16, before 6.1.151 (fixed in 6.1.151); from 6.2, before 6.6.105 (fixed in 6.6.105); from 6.7, before 6.12.46 (fixed in 6.12.46); …

Published 2025-09-19. Last modified 2026-06-17.