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CVE-2026-23457— netfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp()

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基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于sip_help_tcp函数存在整数截断，可能导致解析错误。

CVSS 8.6 · High EPSS 0.43% · P36

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux f5b321bd37fbec9188feb1f721ab46a5ac0b35da< ed81b6a7012485acdb9c6c80735a0b7d8e5e1873 affected
f5b321bd37fbec9188feb1f721ab46a5ac0b35da< cd1b7403ec835f8a0b3f1f7e68ac26af2cb1e42f affected
f5b321bd37fbec9188feb1f721ab46a5ac0b35da< b75209debb9adab287b3caa982f77788c1e15027 affected
f5b321bd37fbec9188feb1f721ab46a5ac0b35da< 528b4509c9dfc272e2e92d811915e5211650d383 affected
f5b321bd37fbec9188feb1f721ab46a5ac0b35da< 75fcaee5170e7dbbee778927134ef2e9568b4659 affected
f5b321bd37fbec9188feb1f721ab46a5ac0b35da< 865dba58958c3a86786f89a501971ab0e3ec6ba9 affected
f5b321bd37fbec9188feb1f721ab46a5ac0b35da< d4f17256544cc37f6534a14a27a9dec3540c2015 affected
f5b321bd37fbec9188feb1f721ab46a5ac0b35da< fbce58e719a17aa215c724473fd5baaa4a8dc57c affected
… +10 more rows
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I. Basic Information for CVE-2026-23457

Vulnerability Information
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Vulnerability Title
netfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp() sip_help_tcp() parses the SIP Content-Length header with simple_strtoul(), which returns unsigned long, but stores the result in unsigned int clen. On 64-bit systems, values exceeding UINT_MAX are silently truncated before computing the SIP message boundary. For example, Content-Length 4294967328 (2^32 + 32) is truncated to 32, causing the parser to miscalculate where the current message ends. The loop then treats trailing data in the TCP segment as a second SIP message and processes it through the SDP parser. Fix this by changing clen to unsigned long to match the return type of simple_strtoul(), and reject Content-Length values that exceed the remaining TCP payload length.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/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基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于sip_help_tcp函数存在整数截断，可能导致解析错误。
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 f5b321bd37fbec9188feb1f721ab46a5ac0b35da ~ ed81b6a7012485acdb9c6c80735a0b7d8e5e1873 -
Linux Linux 2.6.34 -

II. Public POCs for CVE-2026-23457

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III. Intelligence Information for CVE-2026-23457

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Same Patch Batch · Linux · 2026-04-03 · 71 CVEs total

CVE-2026-31402 9.8 CRITICAL nfsd: fix heap overflow in NFSv4.0 LOCK replay cache
CVE-2026-23450 9.8 CRITICAL net/smc: fix NULL dereference and UAF in smc_tcp_syn_recv_sock()
CVE-2026-23427 9.8 CRITICAL ksmbd: fix use-after-free in durable v2 replay of active file handles
CVE-2026-23428 9.8 CRITICAL ksmbd: fix use-after-free of share_conf in compound request
CVE-2026-23455 9.1 CRITICAL netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()
CVE-2026-23461 8.8 HIGH Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user
CVE-2026-23425 8.8 HIGH KVM: arm64: Fix ID register initialization for non-protected pKVM guests
CVE-2026-23462 8.8 HIGH Bluetooth: HIDP: Fix possible UAF
CVE-2026-23456 8.2 HIGH netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case
CVE-2026-23459 8.2 HIGH ip_tunnel: adapt iptunnel_xmit_stats() to NETDEV_PCPU_STAT_DSTATS
CVE-2026-31393 8.1 HIGH Bluetooth: L2CAP: Validate L2CAP_INFO_RSP payload length before access
CVE-2026-31392 8.1 HIGH smb: client: fix krb5 mount with username option
CVE-2026-23466 7.8 HIGH drm/xe: Open-code GGTT MMIO access protection
CVE-2026-23432 7.8 HIGH mshv: Fix use-after-free in mshv_map_user_memory error path
CVE-2026-31398 7.8 HIGH mm/rmap: fix incorrect pte restoration for lazyfree folios
CVE-2026-23437 7.8 HIGH net: shaper: protect late read accesses to the hierarchy
CVE-2026-23458 7.8 HIGH netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()
CVE-2026-23444 7.8 HIGH wifi: mac80211: always free skb on ieee80211_tx_prepare_skb() failure
CVE-2026-23449 7.8 HIGH net/sched: teql: Fix double-free in teql_master_xmit
CVE-2026-23445 7.8 HIGH igc: fix page fault in XDP TX timestamps handling

Showing top 20 of 71 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-23457

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