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CVE-2026-72502— tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF)

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于TCP/IPv6在MTU较大时默认通告MSS未正确限制，导致gso_size可能为0xFFFF并被误认为GSO_BY_FRAGS，进而引发空指针取消引用。

CVSS 7.5 · High EPSS 0.69% · P50

Possible ATT&CK Techniques 1 AI

T1203 · Exploitation for Client Execution

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 3953c46c3ac7eef31a9935427371c6f54a22f1ba< 560b33b434e922ef97f9ff23aa2e909ef7aacd5c affected
3953c46c3ac7eef31a9935427371c6f54a22f1ba< 21f69ac1879bb970588d5e7c12a96e6542f7c1a7 affected
3953c46c3ac7eef31a9935427371c6f54a22f1ba< c0db3dc2ac323b6c4b76adede3b355a9daa6dea8 affected
3953c46c3ac7eef31a9935427371c6f54a22f1ba< 572fff10819dfc359298d1f774839e76a4d96f93 affected
3953c46c3ac7eef31a9935427371c6f54a22f1ba< 8e6214a530c03e341dc1b0a846c8f2b716b3551a affected
3953c46c3ac7eef31a9935427371c6f54a22f1ba< d774cdbda6634a78d0f2baf201ee5a8c57f3bc0e affected
3953c46c3ac7eef31a9935427371c6f54a22f1ba< a210791f33345aa87187f7d7a9f3b9b7f4a28e6d affected
3953c46c3ac7eef31a9935427371c6f54a22f1ba< 2bf43d0e2e6a27d52a7d624e2d6b9116972e8a22 affected
… +10 more rows
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I. Basic Information for CVE-2026-72502

Vulnerability Information
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Vulnerability Title
tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF)
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: tcp: ipv6: clamp default adverting MSS to avoid GSO_BY_FRAGS (0xFFFF) When MTU is large, ip6_default_advmss() can return IPV6_MAXPLEN (65535). This is interpreted by TCP as mss_clamp, allowing the MSS to reach 65535. However, 0xFFFF is also used as a magic value GSO_BY_FRAGS in the kernel. If a TCP packet with gso_size=0xFFFF is passed to skb_segment(), it will be mistakenly treated as GSO_BY_FRAGS, leading to a NULL pointer dereference because local TCP packets do not use frag_list. Fix this by returning min(IPV6_MAXPLEN, GSO_BY_FRAGS - 1) (65534) from ip6_default_advmss() when MTU is large. Also update the stale comment in ip6_default_advmss() which suggested that IPV6_MAXPLEN is returned to mean "any MSS".
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于TCP/IPv6在MTU较大时默认通告MSS未正确限制，导致gso_size可能为0xFFFF并被误认为GSO_BY_FRAGS，进而引发空指针取消引用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 3953c46c3ac7eef31a9935427371c6f54a22f1ba ~ 560b33b434e922ef97f9ff23aa2e909ef7aacd5c -
Linux Linux 4.8 -

II. Public POCs for CVE-2026-72502

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III. Intelligence Information for CVE-2026-72502

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Patches & Fixes for CVE-2026-72502 (8)

Same Patch Batch · Linux · 2026-08-15 · 845 CVEs total

CVE-2026-74475 10.0 CRITICAL vxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-74280 10.0 CRITICAL crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
CVE-2026-74279 10.0 CRITICAL crypto: cavium/cpt - fix DMA cleanup using wrong loop index
CVE-2026-72421 10.0 CRITICAL ipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-72408 10.0 CRITICAL geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-72407 10.0 CRITICAL geneve: validate inner network offset in geneve_gro_complete()
CVE-2026-74309 10.0 CRITICAL vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-72493 9.9 CRITICAL net: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-72041 9.8 CRITICAL espintcp: use sk_msg_free_partial to fix partial send
CVE-2026-74436 9.8 CRITICAL rxrpc: serialize kernel accept preallocation with socket teardown
CVE-2026-72210 9.8 CRITICAL ntfs: fix off-by-one in mapping pairs decoding bounds checks
CVE-2026-72211 9.8 CRITICAL ntfs: grow index root value before reparent header update
CVE-2026-72209 9.8 CRITICAL ntfs: validate attribute values on lookup
CVE-2026-72299 9.8 CRITICAL tipc: restrict socket queue dumps in enqueue tracepoints
CVE-2026-74434 9.8 CRITICAL rxrpc: Don't move a peeked OOB message onto the pending queue
CVE-2026-74433 9.8 CRITICAL rxrpc: Fix UAF in rxgk_issue_challenge()
CVE-2026-72473 9.8 CRITICAL xprtrdma: Decouple req recycling from RPC completion
CVE-2026-72472 9.8 CRITICAL nfs: use nfsi->rwsem to protect traversal of the file lock list
CVE-2026-74545 9.8 CRITICAL rtase: fix double free of multi-frag skb on DMA map failure
CVE-2026-72322 9.8 CRITICAL ipv6: mcast: Fix potential UAF in MLD delayed work

Showing top 20 of 845 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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