Answer in brief
CVE-2025-21759 records a Unknown severity vulnerability in ipv6: mcast: extend RCU protection in igmp6_send(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 <81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a || >=b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 <0bf8e2f3768629d437a32cb824149e6e98254381 || >=b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 <8e92d6a413feaf968a33f0b439ecf27404407458 || >=b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 <087c1faa594fa07a66933d750c0b2610aa1a2946 | 81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a, 0bf8e2f3768629d437a32cb824149e6e98254381, 8e92d6a413feaf968a33f0b439ecf27404407458, 087c1faa594fa07a66933d750c0b2610aa1a2946 |
| Linux/Linuxgeneric | 2.6.26 | Not reported |
Published upstream
Feb 27, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2025-21759 records a Unknown severity vulnerability in ipv6: mcast: extend RCU protection in igmp6_send(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 <81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a || >=b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 <0bf8e2f3768629d437a32cb824149e6e98254381 || >=b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 <8e92d6a413feaf968a33f0b439ecf27404407458 || >=b8ad0cbc58f703972e9e37c4e2a8081dd7e6a551 <087c1faa594fa07a66933d750c0b2610aa1a2946 | 81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a, 0bf8e2f3768629d437a32cb824149e6e98254381, 8e92d6a413feaf968a33f0b439ecf27404407458, 087c1faa594fa07a66933d750c0b2610aa1a2946 |
| Linux/Linuxgeneric | 2.6.26 | Not reported |
Published upstream
Feb 27, 2025
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: ipv6: mcast: extend RCU protection in igmp6_send() igmp6_send() can be called without RTNL or RCU being held. Extend RCU protection so that we can safely fetch the net pointer and avoid a potential UAF. Note that we no longer can use sock_alloc_send_skb() because ipv6.igmp_sk uses GFP_KERNEL allocations which can sleep. Instead use alloc_skb() and charge the net->ipv6.igmp_sk socket under RCU protection.
Quoted source text, attributed separately from HOL analysis.