CVE-2025-21768: net: ipv6: fix dst ref loops in rpl, seg6 and ioam6 lwtunnels
CSIRTS triage
- What
- Reference counting loops in IPv6 rpl, seg6, and ioam6 lightweight tunnels can cause denial of service.
- Who is affected
- Systems using IPv6 routing protocols with rpl, seg6, or ioam6 tunnel configurations.
- Urgency
- Medium; denial of service risk without evidence of active exploitation.
- Action
- Update Linux kernel to include fixes for rpl, seg6, and ioam6 dst reference counting.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21768
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2025-217680.20% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 10% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2025-21768 | coverage & exploitation status | NVD · CVE.org |
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