Medium 5.5Published Sep 19, 2025

CVE-2025-39847ppp: fix memory leak in pad_compress_skb

Updated under an hour ago (Oct 27, 2026, 3:00 AM ET)

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It affects Linux and 3 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Exploited in the last 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.

CVSS: 5.5 MEDIUM (v3.1, NVD)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): Not given
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Linux
NVD analysis: Modified
Record last updated: May 12, 2026
First seen by InfoSec Signals: Oct 19, 2026

Affected products

Affected products

Linux Linux linux:linux (from the name)	from b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c before 9ca6a040f76c0b149293e430dabab446f3fc8ab7; from b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c before 87a35a36742df328d0badf4fbc2e56061c15846c; from b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c before 0b21e9cd4559102da798bdcba453b64ecd7be7ee; from b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c before 1d8b354eafb8876d8bdb1bef69c7d2438aacfbe8; from b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c before 85c1c86a67e09143aa464e9bf09c397816772348; from b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c before 631fc8ab5beb9e0ec8651fb9875b9a968e7b4ae4; from b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c before 33a5bac5f14772730d2caf632ae97b6c2ee95044; from b3f9b92a6ec1a9a5e4b4b36e484f2f62cc73277c before 4844123fe0b853a4982c02666cb3fd863d701d50	CNA record
Siemens SIMATIC CN 4100 siemens:simatic_cn_4100 (from the name)	before V5.0	CISA ADP
linux linux_kernel linux:linux_kernel	from 2.6.15 before 5.4.299; from 5.5 before 5.10.243; from 5.11 before 5.15.192; from 5.16 before 6.1.151; from 6.2 before 6.6.105; from 6.7 before 6.12.46; from 6.13 before 6.16.6; 6.17; and 3 more ranges	NVD
debian debian_linux debian:debian_linux	11.0	NVD

References

References

https://git.kernel.org/stable/c/9ca6a040f76c0b149293e430dabab446f3fc8ab7	patch
https://git.kernel.org/stable/c/87a35a36742df328d0badf4fbc2e56061c15846c	patch
https://git.kernel.org/stable/c/0b21e9cd4559102da798bdcba453b64ecd7be7ee	patch
https://git.kernel.org/stable/c/1d8b354eafb8876d8bdb1bef69c7d2438aacfbe8	patch
https://git.kernel.org/stable/c/85c1c86a67e09143aa464e9bf09c397816772348	patch
https://git.kernel.org/stable/c/631fc8ab5beb9e0ec8651fb9875b9a968e7b4ae4	patch
https://git.kernel.org/stable/c/33a5bac5f14772730d2caf632ae97b6c2ee95044	patch
https://git.kernel.org/stable/c/4844123fe0b853a4982c02666cb3fd863d701d50	patch
https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html	mailing-list, third-party-advisory
https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html	mailing-list, third-party-advisory
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.