Skip to main content

CWE-911

Improper Update of Reference Count

14 CVEs Avg CVSS 6.9 MITRE
1
CRITICAL
9
HIGH
3
MEDIUM
1
LOW
2
POC
0
KEV

Monthly

CVE-2026-77587 Aug 20, 20:47 MEDIUM PATCH This Month

Use-after-free and potential double-free in Tor's conflux subsystem before version 0.4.9.11 enables a malicious exit node to crash Tor clients by triggering memory corruption during circuit recovery. The defect activates when a recovery leg attempts to revive a conflux set whose last linked leg has already been deallocated, resulting in access to freed memory and a possible second free of the same object. No public exploit is identified at time of analysis, but exploitation requires only that an attacker control a malicious exit node within the Tor network, a non-trivial but achievable position for motivated threat actors.

Denial Of Service Tor Torproject
NVD
CVSS 3.1
5.9
EPSS
0.2%
CVE-2026-49419 Aug 19, 04:32 HIGH This Week

Reference count underflow in FreeBSD's jail subsystem allows an unprivileged local user to double-free a prison structure, yielding two distinct impact paths: on the jail host, this reliably causes an immediate kernel panic, while a user already running inside a jail may be able to exploit the freed structure while still in use to escape the jail and elevate privileges to the host. Affected releases are FreeBSD 15.0-RELEASE before patch level 11 and FreeBSD 15.1-RELEASE before patch level 1, per FreeBSD Security Advisory SA-26:38. EPSS is currently 0.16% (5th percentile) and SSVC classifies exploitation as 'none', suggesting no observed in-the-wild activity, but SSVC technical impact is rated 'total', reflecting the severity of the jail-escape scenario.

Information Disclosure Freebsd
NVD VulDB
CVSS 3.1
8.8
EPSS
0.2%
CVE-2026-19380 Aug 10, 00:15 LOW POC Monitor

Local availability degradation in Mullvad's wireguard.sys kernel driver 0.10.1 stems from improper reference count management (CWE-911) within the AdapterState function of the IOCTL handler. An attacker with high local privileges can trigger this defect to cause driver instability or crash the WireGuard adapter, impacting VPN connectivity. A public proof-of-concept exploit exists; however, this vulnerability is not listed in CISA's Known Exploited Vulnerabilities catalog and carries a CVSS 4.0 score of 4.6, reflecting its constrained impact and access prerequisites.

Information Disclosure Wireguard Sys Mullvad
NVD VulDB
CVSS 4.0
1.8
EPSS
0.1%
CVE-2026-52943 Jun 24, 09:00 HIGH PATCH This Week

Local privilege escalation in the Linux kernel networking stack (skbuff/MSG_ZEROCOPY path) allows an unprivileged local user to gain full root via a use-after-free on ubuf_info_msgzc. The pskb_carve_inside_header() and pskb_carve_inside_nonlinear() helpers memcpy the skb_shared_info (including the zerocopy destructor_arg/uarg pointer) into a new buffer without calling net_zcopy_get(), so the uarg refcount is decremented more times than it was incremented, freeing the ubuf_info while live TX skbs still reference it. A working proof-of-concept exists that achieves reliable root escalation on a default kernel configuration; the issue is not listed in CISA KEV and EPSS probability is low (0.21%, 11th percentile).

Privilege Escalation Linux Red Hat Suse
NVD VulDB
CVSS 3.1
7.8
EPSS
0.2%
CVE-2026-46316 Jun 09, 11:52 CRITICAL PATCH Act Now

Use-after-free in the KVM arm64 vGIC-ITS translation cache allows a malicious guest to corrupt host kernel memory by triggering concurrent cache invalidations that double-drop a single reference. The flaw affects Linux 6.10 and later until the stable backports, has no public exploit identified at time of analysis, and EPSS rates real-world exploitation probability as very low (0.02%, 5th percentile) despite the CVSS 9.3 rating.

Information Disclosure Linux
NVD VulDB
CVSS 3.1
9.3
EPSS
0.0%
CVE-2026-46099 May 27, 14:17 HIGH PATCH This Week

Use-after-free in the Linux kernel's IPv6 SR (seg6) and RPL lightweight tunnel input paths can be triggered on PREEMPT_RT builds when a higher-priority task races ksoftirqd during a concurrent FIB lookup on a shared nexthop. The flaw causes dst_cache_set_ip6() to call dst_hold() on a freed per-CPU route, producing a kernel warning or memory corruption that an attacker on the network could leverage for denial of service or potential code execution. EPSS is very low (0.02%) and there is no public exploit identified at time of analysis.

Information Disclosure Linux
NVD VulDB
CVSS 3.1
8.1
EPSS
0.0%
CVE-2024-45783 Feb 18, 20:15 MEDIUM PATCH This Month

A flaw was found in grub2. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.

Denial Of Service
NVD VulDB
CVSS 3.1
4.4
EPSS
0.1%
CVE-2024-46972 Dec 28, 05:15 HIGH This Week

Software installed and run as a non-privileged user may conduct improper GPU system calls to trigger use-after-free kernel exceptions. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.

Information Disclosure
NVD
CVSS 3.1
7.8
EPSS
0.2%
CVE-2023-5633 Oct 23, 22:15 HIGH PATCH This Week

The reference count changes made as part of the CVE-2023-33951 and CVE-2023-33952 fixes exposed a use-after-free flaw in the way memory objects were handled when they were being used to store a. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.

Privilege Escalation Red Hat VMware Codeready Linux Builder Codeready Linux Builder For Arm64 +20
NVD
CVSS 3.1
7.8
EPSS
0.3%
CVE-2023-2019 Apr 24, 21:15 MEDIUM PATCH This Month

A flaw was found in the Linux kernel's netdevsim device driver, within the scheduling of events. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity.

Denial Of Service Linux Red Hat Enterprise Linux Linux Kernel
NVD GitHub
CVSS 3.1
4.4
EPSS
0.3%
EPSS 0% CVSS 5.9
MEDIUM PATCH This Month

Use-after-free and potential double-free in Tor's conflux subsystem before version 0.4.9.11 enables a malicious exit node to crash Tor clients by triggering memory corruption during circuit recovery. The defect activates when a recovery leg attempts to revive a conflux set whose last linked leg has already been deallocated, resulting in access to freed memory and a possible second free of the same object. No public exploit is identified at time of analysis, but exploitation requires only that an attacker control a malicious exit node within the Tor network, a non-trivial but achievable position for motivated threat actors.

Denial Of Service Tor Torproject
NVD
EPSS 0% CVSS 8.8
HIGH This Week

Reference count underflow in FreeBSD's jail subsystem allows an unprivileged local user to double-free a prison structure, yielding two distinct impact paths: on the jail host, this reliably causes an immediate kernel panic, while a user already running inside a jail may be able to exploit the freed structure while still in use to escape the jail and elevate privileges to the host. Affected releases are FreeBSD 15.0-RELEASE before patch level 11 and FreeBSD 15.1-RELEASE before patch level 1, per FreeBSD Security Advisory SA-26:38. EPSS is currently 0.16% (5th percentile) and SSVC classifies exploitation as 'none', suggesting no observed in-the-wild activity, but SSVC technical impact is rated 'total', reflecting the severity of the jail-escape scenario.

Information Disclosure Freebsd
NVD VulDB
EPSS 0% CVSS 1.8
LOW POC Monitor

Local availability degradation in Mullvad's wireguard.sys kernel driver 0.10.1 stems from improper reference count management (CWE-911) within the AdapterState function of the IOCTL handler. An attacker with high local privileges can trigger this defect to cause driver instability or crash the WireGuard adapter, impacting VPN connectivity. A public proof-of-concept exploit exists; however, this vulnerability is not listed in CISA's Known Exploited Vulnerabilities catalog and carries a CVSS 4.0 score of 4.6, reflecting its constrained impact and access prerequisites.

Information Disclosure Wireguard Sys Mullvad
NVD VulDB
EPSS 0% CVSS 7.8
HIGH PATCH This Week

Local privilege escalation in the Linux kernel networking stack (skbuff/MSG_ZEROCOPY path) allows an unprivileged local user to gain full root via a use-after-free on ubuf_info_msgzc. The pskb_carve_inside_header() and pskb_carve_inside_nonlinear() helpers memcpy the skb_shared_info (including the zerocopy destructor_arg/uarg pointer) into a new buffer without calling net_zcopy_get(), so the uarg refcount is decremented more times than it was incremented, freeing the ubuf_info while live TX skbs still reference it. A working proof-of-concept exists that achieves reliable root escalation on a default kernel configuration; the issue is not listed in CISA KEV and EPSS probability is low (0.21%, 11th percentile).

Privilege Escalation Linux Red Hat +1
NVD VulDB
EPSS 0% CVSS 9.3
CRITICAL PATCH Act Now

Use-after-free in the KVM arm64 vGIC-ITS translation cache allows a malicious guest to corrupt host kernel memory by triggering concurrent cache invalidations that double-drop a single reference. The flaw affects Linux 6.10 and later until the stable backports, has no public exploit identified at time of analysis, and EPSS rates real-world exploitation probability as very low (0.02%, 5th percentile) despite the CVSS 9.3 rating.

Information Disclosure Linux
NVD VulDB
EPSS 0% CVSS 8.1
HIGH PATCH This Week

Use-after-free in the Linux kernel's IPv6 SR (seg6) and RPL lightweight tunnel input paths can be triggered on PREEMPT_RT builds when a higher-priority task races ksoftirqd during a concurrent FIB lookup on a shared nexthop. The flaw causes dst_cache_set_ip6() to call dst_hold() on a freed per-CPU route, producing a kernel warning or memory corruption that an attacker on the network could leverage for denial of service or potential code execution. EPSS is very low (0.02%) and there is no public exploit identified at time of analysis.

Information Disclosure Linux
NVD VulDB
EPSS 0% CVSS 4.4
MEDIUM PATCH This Month

A flaw was found in grub2. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity. No vendor patch available.

Denial Of Service
NVD VulDB
EPSS 0% CVSS 7.8
HIGH This Week

Software installed and run as a non-privileged user may conduct improper GPU system calls to trigger use-after-free kernel exceptions. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity. No vendor patch available.

Information Disclosure
NVD
EPSS 0% CVSS 7.8
HIGH PATCH This Week

The reference count changes made as part of the CVE-2023-33951 and CVE-2023-33952 fixes exposed a use-after-free flaw in the way memory objects were handled when they were being used to store a. Rated high severity (CVSS 7.8), this vulnerability is low attack complexity.

Privilege Escalation Red Hat VMware +22
NVD
EPSS 0% CVSS 4.4
MEDIUM PATCH This Month

A flaw was found in the Linux kernel's netdevsim device driver, within the scheduling of events. Rated medium severity (CVSS 4.4), this vulnerability is low attack complexity.

Denial Of Service Linux Red Hat +2
NVD GitHub

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy