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High severity7.8NVD Advisory· Published Feb 27, 2025· Updated May 12, 2026

CVE-2025-21760

CVE-2025-21760

Description

In the Linux kernel, the following vulnerability has been resolved:

ndisc: extend RCU protection in ndisc_send_skb()

ndisc_send_skb() can be called without RTNL or RCU held.

Acquire rcu_read_lock() earlier, so that we can use dev_net_rcu() and avoid a potential UAF.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

CVE-2025-21760 fixes a use-after-free in Linux kernel's ndisc_send_skb() due to missing RCU protection.

Vulnerability

The vulnerability resides in the Linux kernel's neighbor discovery (NDISC) subsystem. The function ndisc_send_skb() could be invoked without holding the RCU read lock or RTNL, leading to a potential use-after-free (UAF) condition. The proper fix extends RCU protection earlier in the call path, allowing the use of dev_net_rcu() to safely access network namespace data.

Attack

Vector

An attacker may exploit this flaw by sending crafted neighbor discovery messages that trigger ndisc_send_skb() under race conditions. No special privileges beyond network access are required, making it exploitable from a local network position.

Impact

A successful exploit can cause a use-after-free, leading to system memory corruption. This may result in a denial of service (system crash) or potentially privilege escalation, depending on the attacker's ability to control freed memory.

Mitigation

The fix has been included in the Linux kernel stable releases. Users are advised to update their kernels. Affected products include Siemens SIMATIC S7-1500 TM MFP with GNU/Linux subsystem [1].

References
  1. SSA-265688

AI Insight generated on May 20, 2026. Synthesized from this CVE's description and the cited reference URLs; citations are validated against the source bundle.

Affected products

167

Patches

0

No patches discovered yet.

Vulnerability mechanics

AI mechanics synthesis has not run for this CVE yet.

References

11

News mentions

0

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