CVE intelligence and bounded remediation

CVE-2025-39847 — Linux Linux Kernel security vulnerability

Medium CVSS 5.5

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.

Severity
Medium
CVSS
5.5 (3.1)
Published
2025-09-19
CISA KEV
Not currently listed
Ecosystem
linux/kernel
Weaknesses
CWE-401

Affected products

  • linux / linux_kernel
  • linux / linux_kernel / 6.17
  • debian / debian_linux / 11.0

Showing 3 representative product identities from 12 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Resource exhaustion and denial of service

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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