VulnerabilityPublished 27 Dec 2024Updated 13 Oct 2026

CVE-2024-56643: Linux kernel · dccp: Fix memory leak in dccp_feat_change_recv

Affects Linux kernelSource GCVE Database

Not known to be exploited · CVSS 5.5 Medium · fixed in 4.4.0-1156.162 : update Linux kernel when convenient.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

5.5Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.4.0-1156.162, 4.15.0-1205.220~14.04.1, 4.4.0-283.317~14.04.1 +105

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Local
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Local: The vulnerable component is not bound to the network stack and the attacker’s path is via read/write/execute capabilities. Either: the attacker exploits the vulnerability by accessing the target system locally (e.g., keyboard, console), or remotely (e.g., SSH); or the attacker relies on User Interaction by another person to perform actions required to exploit the vulnerability (e.g., tricking a legitimate user into opening a malicious document).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Dec 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Patches and advisories

Affected software

Product	Affected	Fixed in
Ubuntu 24.04 LTSlinux`pkg:deb/ubuntu/linux?arch=source&distro=noble`Other threats	Affected <6.8.0-58.60	Fixed in 6.8.0-58.60
Ubuntu 24.04 LTSlinux-aws`pkg:deb/ubuntu/linux-aws?arch=source&distro=noble`Other threats	Affected <6.8.0-1027.29	Fixed in 6.8.0-1027.29
Ubuntu 24.04 LTSlinux-azure`pkg:deb/ubuntu/linux-azure?arch=source&distro=noble`Other threats	Affected <6.8.0-1027.32	Fixed in 6.8.0-1027.32
Ubuntu 24.04 LTSlinux-azure-6.11`pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=noble`Other threats	Affected <6.11.0-1012.12~24.04.1	Fixed in 6.11.0-1012.12~24.04.1
Ubuntu 24.04 LTSlinux-azure-nvidia`pkg:deb/ubuntu/linux-azure-nvidia?arch=source&distro=noble`Other threats	Affected <6.8.0-1014.15	Fixed in 6.8.0-1014.15
Ubuntu 24.04 LTSlinux-gcp`pkg:deb/ubuntu/linux-gcp?arch=source&distro=noble`Other threats	Affected <6.8.0-1028.30	Fixed in 6.8.0-1028.30

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

In the Linux kernel, the following vulnerability has been resolved: dccp: Fix memory leak in dccp_feat_change_recv If dccp_feat_push_confirm() fails after new value for SP feature was accepted without reconciliation ('entry == NULL' branch), memory allocated for that value with dccp_feat_clone_sp_val() is never freed. Here is the kmemleak stack for this: unreferenced object 0xffff88801d4ab488 (size 8): comm "syz-executor310", pid 1127, jiffies 4295085598 (age 41.666s) hex dump (first 8 bytes): 01 b4 4a 1d 80 88 ff ff ..J..... backtrace: [<00000000db7cabfe>] kmemdup+0x23/0x50 mm/util.c:128 [<0000000019b38405>] kmemdup include/linux/string.h:465 [inline] [<0000000019b38405>] dccp_feat_clone_sp_val net/dccp/feat.c:371 [inline] [<0000000019b38405>] dccp_feat_clone_sp_val net/dccp/feat.c:367 [inline] [<0000000019b38405>] dccp_feat_change_recv net/dccp/feat.c:1145 [inline] [<0000000019b38405>] dccp_feat_parse_options+0x1196/0x2180 net/dccp/feat.c:1416 [<00000000b1f6d94a>] dccp_parse_options+0xa2a/0x1260 net/dccp/options.c:125 [<0000000030d7b621>] dccp_rcv_state_process+0x197/0x13d0 net/dccp/input.c:650 [<000000001f74c72e>] dccp_v4_do_rcv+0xf9/0x1a0 net/dccp/ipv4.c:688 [<00000000a6c24128>] sk_backlog_rcv include/net/sock.h:1041 [inline] [<00000000a6c24128>] __release_sock+0x139/0x3b0 net/core/sock.c:2570 [<00000000cf1f3a53>] release_sock+0x54/0x1b0 net/core/sock.c:3111 [<000000008422fa23>] inet_wait_for_connect net/ipv4/af_inet.c:603 [inline] [<000000008422fa23>] __inet_stream_connect+0x5d0/0xf70 net/ipv4/af_inet.c:696 [<0000000015b6f64d>] inet_stream_connect+0x53/0xa0 net/ipv4/af_inet.c:735 [<0000000010122488>] __sys_connect_file+0x15c/0x1a0 net/socket.c:1865 [<00000000b4b70023>] __sys_connect+0x165/0x1a0 net/socket.c:1882 [<00000000f4cb3815>] __do_sys_connect net/socket.c:1892 [inline] [<00000000f4cb3815>] __se_sys_connect net/socket.c:1889 [inline] [<00000000f4cb3815>] __x64_sys_connect+0x6e/0xb0 net/socket.c:1889 [<00000000e7b1e839>] do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 [<0000000055e91434>] entry_SYSCALL_64_after_hwframe+0x67/0xd1 Clean up the allocated memory in case of dccp_feat_push_confirm() failure and bail out with an error reset code. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

GCVE source: db.gcve.eu
OSV ID: UBUNTU-CVE-2024-56643
Osv Schema Version: 1.7.0
Ecosystems: Ubuntu:Pro:14.04:LTS, Ubuntu:Pro:16.04:LTS, Ubuntu:16.04:LTS, Ubuntu:Pro:FIPS-updates:16.04:LTS, Ubuntu:Pro:FIPS:16.04:LTS, Ubuntu:Pro:18.04:LTS, Ubuntu:18.04:LTS, Ubuntu:Pro:FIPS-updates:18.04:LTS, Ubuntu:Pro:FIPS:18.04:LTS, Ubuntu:20.04:LTS, Ubuntu:Pro:20.04:LTS, Ubuntu:Pro:FIPS-updates:20.04:LTS, Ubuntu:Pro:FIPS:20.04:LTS, Ubuntu:22.04:LTS, Ubuntu:Nvidia-BlueField:22.04:LTS, Ubuntu:Pro:Realtime:22.04:LTS, Ubuntu:Pro:FIPS-preview:22.04:LTS, Ubuntu:Pro:FIPS-updates:22.04:LTS, Ubuntu:24.04:LTS, Ubuntu:Pro:Realtime:24.04:LTS, Ubuntu:Pro:FIPS-updates:24.04:LTS
CVSS version: 3.1

References

Community reviews

Loading reviews…