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.
Conclusion & alert: CVE-2025-21759 is rated High Risk (68.9/100): CVSS High severity, with high exploitation likelihood (EPSS 7.01%, 93th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +6.73% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 0.28% | 7.01% | +6.73% |
| 2 | 2026-05-15 | 0.56% | 0.28% | -0.28% |
| 3 | 2026-04-21 | — | 0.56% | — |
Full EPSS history (7 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.8 | 3.1 | HIGH |
|
1.8 | 5.9 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2025-21759 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. | https://security-tracker.debian.org/tracker/CVE-2025-21759 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2025-21759 |
suse
|
medium | — | https://www.suse.com/security/cve/CVE-2025-21759/ |
ubuntu
|
medium | CVE-2025-21759 medium priority: Ubuntu including 158 source packages (linux, linux-allwinner-5.19, …), 1551 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 1145, ignored 154, released 135, needed 74, not-affected 43. | https://ubuntu.com/security/CVE-2025-21759 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| linux | linux_kernel | >= 2.6.26, < 6.6.79 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.7, < 6.12.16 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | >= 6.13, < 6.13.4 | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* |
| linux | linux_kernel | 6.14 | cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:* |
| linux | linux_kernel | 6.14 | cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:* |