cve-2026-53362

HIGH CVSS 7.8 nvd
Description

In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.

Timeline
Published
2026-07-04
Last Modified
2026-10-15
CVSS Details
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
Affected Products
  • linux linux_kernel
  • siemens simatic_s7-1500_tm_mfp_firmware
  • siemens simatic_s7-1500_tm_mfp
CISA KEV — Known Exploited Vulnerability
Name
Linux Kernel Unspecified Vulnerability
Added to KEV
2026-08-27
Action due
2026-08-30
Required action
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Weaknesses (CWE)
CVSS metrics
Version Base Severity Vector Exploitability Impact Source
3.1 7.8 HIGH CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H 1.8 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67
CPE configurations
OR
CPE Version range Vulnerable
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* >= 6.0, < 6.1.177 yes
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* >= 6.2, < 6.6.144 yes
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* >= 6.7, < 6.12.95 yes
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* >= 6.13, < 6.18.38 yes
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* >= 6.19, < 7.1.3 yes
OR
CPE Version range Vulnerable
cpe:2.3:o:siemens:simatic_s7-1500_tm_mfp_firmware:-:*:*:*:*:*:*:* — yes
OR
CPE Version range Vulnerable
cpe:2.3:h:siemens:simatic_s7-1500_tm_mfp:-:*:*:*:*:*:*:* — no
NVD metadata
NVD status
Analyzed
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
Linked Vulnerabilities

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  "datePublished": "2026-07-04T12:17:02.113",
  "dateUpdated": "2026-10-15T13:46:55.187",
  "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: account for fraggap on the paged allocation path\n\nIn __ip6_append_data(), when the paged-allocation branch is taken\n(MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are\ncomputed as\n\n\talloclen = fragheaderlen + transhdrlen;\n\tpagedlen = datalen - transhdrlen;\n\ndatalen already includes fraggap (datalen = length + fraggap). When\nfraggap is non-zero, this is not the first skb and transhdrlen is zero.\nThe fraggap bytes carried over from the previous skb are copied just past\nthe fragment headers in the new skb's linear area. The linear area is\ntherefore undersized by fraggap bytes while pagedlen is overstated by the\nsame amount, and the copy writes past skb->end into the trailing\nskb_shared_info.\n\nAn unprivileged user can trigger this via a UDPv6 socket using\nMSG_MORE together with MSG_SPLICE_PAGES.\n\nThe bad accounting was introduced by commit 773ba4fe9104 (\"ipv6:\navoid partial copy for zc\"). Before commit ce650a166335 (\"udp6: Fix\n__ip6_append_data()'s handling of MSG_SPLICE_PAGES\"), the negative\ncopy value caused -EINVAL to be returned. That later commit allowed\nMSG_SPLICE_PAGES to proceed in this case, making the corruption\ntriggerable.\n\nThe non-paged branch sets alloclen to fraglen, which already accounts\nfor fraggap because datalen does. Bring the paged branch in line by\nadding fraggap to alloclen and subtracting it from pagedlen.\n\nAfter this adjustment, copy no longer collapses to -fraggap on the\npaged path, so remove the stale comment describing that old arithmetic.\nSince a negative copy is no longer expected for a valid MSG_SPLICE_PAGES\ncase, remove the MSG_SPLICE_PAGES exception from the negative copy check.",
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  "title": "In the Linux kernel, the following vulnerability has been resolved:\n\nipv6: account for fraggap on the paged allocatio..."
}
Enrichment data
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