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CVE-2026-52986— netfilter: nf_conntrack_sip: don't use simple_strtoul

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基金会开源的操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于nf_conntrack_sip中使用了不安全的simple_strtoul函数进行端口解析，缺少边界检查，可能导致攻击者通过畸形数据包造成影响。

CVSS 9.8 · Critical EPSS 0.63% · P49

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 05e3ced297fe755093140e7487e292fb7603316e< 8cd0358379570003659186706e077929d6930c40 affected
05e3ced297fe755093140e7487e292fb7603316e< 9c6afcb1c3cbb2c0da65b8515ac14d7273872f84 affected
05e3ced297fe755093140e7487e292fb7603316e< b3264c977e79d8a25778d4fd11520f00fea1329c affected
05e3ced297fe755093140e7487e292fb7603316e< ea2ecd29b8f4433e52607192ca91084f95787ca0 affected
05e3ced297fe755093140e7487e292fb7603316e< 9f69c323ae0ab517e595c2cc74e0ae0d9d085611 affected
05e3ced297fe755093140e7487e292fb7603316e< 7df9863bf538a626e8a684e59cb2c43eac0ef3c8 affected
05e3ced297fe755093140e7487e292fb7603316e< 523762e3b6933fff81f01dfa3c60c0774044cdab affected
05e3ced297fe755093140e7487e292fb7603316e< 8cf6809cddcbe301aedfc6b51bcd4944d45795f6 affected
… +10 more rows
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I. Basic Information for CVE-2026-52986

Vulnerability Information
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Vulnerability Title
netfilter: nf_conntrack_sip: don't use simple_strtoul
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: don't use simple_strtoul Replace unsafe port parsing in epaddr_len(), ct_sip_parse_header_uri(), and ct_sip_parse_request() with a new sip_parse_port() helper that validates each digit against the buffer limit, eliminating the use of simple_strtoul() which assumes NUL-terminated strings. The previous code dereferenced pointers without bounds checks after sip_parse_addr() and relied on simple_strtoul() on non-NUL-terminated skb data. A port that reaches the buffer limit without a trailing character is also rejected as malformed. Also get rid of all simple_strtoul() usage in conntrack, prefer a stricter version instead. There are intentional changes: - Bail out if number is > UINT_MAX and indicate a failure, same for too long sequences. While we do accept 05535 as port 5535, we will not accept e.g. 'sip:10.0.0.1:005060'. While its syntactically valid under RFC 3261, we should restrict this to not waste cycles when presented with malformed packets with 64k '0' characters. - Force base 10 in ct_sip_parse_numerical_param(). This is used to fetch 'expire=' and 'rports='; both are expected to use base-10. - In nf_nat_sip.c, only accept the parsed value if its within the 1k-64k range. - epaddr_len now returns 0 if the port is invalid, as it already does for invalid ip addresses. This is intentional. nf_conntrack_sip performs lots of guesswork to find the right parts of the message to parse. Being stricter could break existing setups. Connection tracking helpers are designed to allow traffic to pass, not to block it. Based on an earlier patch from Jenny Guanni Qu <qguanni@gmail.com>.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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基金会开源的操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于nf_conntrack_sip中使用了不安全的simple_strtoul函数进行端口解析，缺少边界检查，可能导致攻击者通过畸形数据包造成影响。
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 05e3ced297fe755093140e7487e292fb7603316e ~ 8cd0358379570003659186706e077929d6930c40 -
Linux Linux 2.6.26 -

II. Public POCs for CVE-2026-52986

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III. Intelligence Information for CVE-2026-52986

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Patches & Fixes for CVE-2026-52986 (8)

Same Patch Batch · Linux · 2026-06-24 · 219 CVEs total

CVE-2026-53046 9.8 CRITICAL ksmbd: fix use-after-free from async crypto on Qualcomm crypto engine
CVE-2026-53088 9.8 CRITICAL net: bcmgenet: fix off-by-one in bcmgenet_put_txcb
CVE-2026-53010 9.8 CRITICAL ksmbd: fix use-after-free in smb2_open during durable reconnect
CVE-2026-53006 9.8 CRITICAL ipv6: fix possible UAF in icmpv6_rcv()
CVE-2026-53086 9.8 CRITICAL net: bcmgenet: fix racing timeout handler
CVE-2026-53002 9.8 CRITICAL netfilter: conntrack: remove sprintf usage
CVE-2026-52993 9.8 CRITICAL tipc: fix double-free in tipc_buf_append()
CVE-2026-52989 9.8 CRITICAL nvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers
CVE-2026-52982 9.8 CRITICAL net: usb: rtl8150: fix use-after-free in rtl8150_start_xmit()
CVE-2026-53045 9.8 CRITICAL memory: tegra124-emc: Fix dll_change check
CVE-2026-52955 9.8 CRITICAL libceph: Fix potential out-of-bounds access in crush_decode()
CVE-2026-53049 9.8 CRITICAL gfs2: add some missing log locking
CVE-2026-52931 9.8 CRITICAL batman-adv: tp_meter: avoid use of uninit sender vars
CVE-2026-53055 9.8 CRITICAL crypto: hisilicon/sec2 - prevent req used-after-free for sec
CVE-2026-52924 9.8 CRITICAL sctp: purge outqueue on stale COOKIE-ECHO handling
CVE-2026-52914 9.8 CRITICAL batman-adv: fix fragment reassembly length accounting
CVE-2026-52999 9.1 CRITICAL netfilter: nfnetlink_osf: fix out-of-bounds read on option matching
CVE-2026-53043 9.1 CRITICAL ocfs2/dlm: validate qr_numregions in dlm_match_regions()
CVE-2026-52958 9.1 CRITICAL libceph: Fix potential out-of-bounds access in osdmap_decode()
CVE-2026-52918 8.8 HIGH Bluetooth: serialize accept_q access

Showing top 20 of 219 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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