CVE Watchtower

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CVE-2026-63912NVD

Vulnerability Summary

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

xfrm: esp: restore combined single-frag length gate

The ESP out-of-place fast path appends the trailer in esp_output_head()
before esp_output_tail() allocates the destination page frag. The
head-side gate currently checks skb->data_len and tailen separately, but
the tail code allocates a single destination frag from the combined
post-trailer skb->data_len.

Reject the page-frag fast path when the combined aligned length exceeds a
page. Otherwise skb_page_frag_refill() may fall back to a single page while
the destination sg still spans the combined skb->data_len.

Restore this combined-length page gate for both IPv4 and IPv6.
Severity Level
CRITICAL(9.8)
Published Date
Jul 19, 2026
Last Modified
Oct 30, 2026
Exploitation Status
No confirmed exploitation yet
EPSS Score (30-Day)
0.71%Probability
Root Weakness (CWE)
The software reads data past the end, or before the beginning, of the intended buffer.
CVSS v3.1 Base Metrics — Score 9.8 (CRITICAL)
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

Affected & Patched Versions

Affected Versions
  • Linux Linux Kernel >= 4.14.288 and < 4.15
  • Linux Linux Kernel >= 4.19.252 and < 4.20
  • Linux Linux Kernel >= 5.4.205 and < 5.5
  • Linux Linux Kernel >= 5.10.113 and < 5.10.259
  • Linux Linux Kernel >= 5.15.36 and < 5.15.210
  • Linux Linux Kernel >= 5.17.5 and < 5.18
  • Linux Linux Kernel >= 5.18.1 and < 6.1.176
  • Linux Linux Kernel >= 6.2 and < 6.6.143
  • Linux Linux Kernel >= 6.7 and < 6.12.93
  • Linux Linux Kernel >= 6.13 and < 6.18.35
  • Linux Linux Kernel >= 6.19 and < 7.0.12
  • Linux Linux Kernel
Patched Versions
  • Linux Linux Kernel 4.15
  • Linux Linux Kernel 4.20
  • Linux Linux Kernel 5.5
  • Linux Linux Kernel 5.10.259
  • Linux Linux Kernel 5.15.210
  • Linux Linux Kernel 5.18
  • Linux Linux Kernel 6.1.176
  • Linux Linux Kernel 6.6.143
  • Linux Linux Kernel 6.12.93
  • Linux Linux Kernel 6.18.35
  • Linux Linux Kernel 7.0.12
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🎁7-Day Free Trial — Try Pro or Team, no card required.
📧Email Delivery — Threat intel straight to your inbox.
♾️Unlimited Vendors — Track your entire stack.
🚨All New CVEs — Be the first to know.
📈EPSS Spike Alerts — Catch rising risk before it peaks.
🎯Custom EPSS/CVSS — Filter noise, focus on risk.
🛡️Exploit Intel — A 2nd confirmed-exploit signal beyond KEV.
🐙GitHub Issues — Auto-tracked, no duplicates.
📬Weekly Digest — One clean summary, not inbox spam.
🏷️Watchlist Groups — Tag alerts by team (Infra/AppSec/SOC).
💬Webhooks — Slack & Teams integration.
🔀Smart Routing — Critical alerts to one channel, rest to another.
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