How severe is CVE-2026-53363?

CVE-2026-53363 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-53363 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-53363?

CVE-2026-53363 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-53363?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-53363 published?

CVE-2026-53363 was published on 2026-07-10 and last updated on 2026-07-22.

CVE-2026-53363

CVE-2026-53363 is a critical-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
EPSS exploit prediction: 0% (22nd percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Linux Linux Kernel
Published: 2026-07-10
Last modified: 2026-07-22

Description

In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: preserve shared-frag marker in iptfs_consume_frags() iptfs_consume_frags() transfers paged fragments from one socket buffer to another but fails to propagate the SKBFL_SHARED_FRAG flag. This is the same class of bug that was fixed in skb_try_coalesce() for CVE-2026-46300: when fragments backed by read-only page-cache pages are merged, the marker indicating their shared nature must be preserved so that ESP can decide correctly whether in-place encryption is safe. Apply the same two-line fix used in skb_try_coalesce() to iptfs_consume_frags().

Frequently asked questions

What is CVE-2026-53363?: In the Linux kernel, the following vulnerability has been resolved: xfrm: iptfs: preserve shared-frag marker in iptfs_consume_frags() iptfs_consume_frags() transfers paged fragments from one socket buffer to another but fails to propagate the SKBFL_SHARED_FRAG flag. This is the same class of bug that was fixed in skb_try_coalesce() for CVE-2026-46300: when fragments backed by read-only page-cache pages are merged, the marker indicating their shared nature must be preserved so that ESP can decide correctly whether in-place encryption is safe. Apply the same two-line fix used in skb_try_coalesce() to iptfs_consume_frags().
How severe is CVE-2026-53363?: CVE-2026-53363 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-53363 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (22nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-53363?: CVE-2026-53363 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-53363?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-53363 published?: CVE-2026-53363 was published on 2026-07-10 and last updated on 2026-07-22.

References

Affected products (8)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc7:*:*:*:*:*:*

More vulnerabilities in Linux Linux Kernel

CVE-2026-63795 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: 9p: avoid putting oldfid in p9_client_walk() error…
CVE-2025-38429 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: bus: mhi: ep: Update read pointer only after…
CVE-2025-22021 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: netfilter: socket: Lookup orig tuple for IPv6…
CVE-2025-21663 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: net: stmmac: dwmac-tegra: Read iommu stream id…
CVE-2024-56719 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: net: stmmac: fix TSO DMA API usage causing…
CVE-2024-44984 — Critical (CVSS 10.0): In the Linux kernel, the following vulnerability has been resolved: bnxt_en: Fix double DMA unmapping for…

All CVEs affecting Linux Linux Kernel →