CVE-2026-55653
A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) cl
CVSS
4.3
Medium
EPSS
0.2%
p15
KEV
—
Exploit Today
5
0-100
Published: Jun 23, 2026 · Last modified: Jul 8, 2026 · CWE-415
0.2%EPSS · 30 days0.2%
2026-06-302026-07-18
A flaw was found in OpenSSH. A malicious SSH server can exploit a double free vulnerability in the Diffie-Hellman Group Exchange (DH-GEX) client path. This occurs during FIPS (Federal Information Processing Standards) mode known-group validation when the client processes attacker-controlled DH-GEX group parameters. Successful exploitation leads to client-side process termination, resulting in a Denial of Service (DoS).
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-239188.8 HIG98.7%
——30Double Free and possible RCE vulnerability in Apache HTTP Server with the HTTP/2 protocol.
This issue affects Apache HTTP Server: 2.4.66.
Users are recommended to upgrade to version 2.4.67, which fixes the issue.4dCVE-2026-89259.8 CRI61.4%
——18The curl logic that works with SASL authentication could end up cleaning up
the GSASL context *twice* without clearing the pointer in between, making it
`free()` the same pointer twice.12dCVE-2026-338117.5 HIG52.9%
——16When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.2dCVE-2026-506857.5 HIG45.6%
——14Double free in Windows DHCP Server allows an authorized attacker to execute code over a network.4dCVE-2026-430119.8 CRI44.4%
——13In the Linux kernel, the following vulnerability has been resolved:
net/x25: Fix potential double free of skb
When alloc_skb fails in x25_queue_rx_frame it calls kfree_skb(skb) at
line 48 and returns 1 (error).
This error propagates back through the call chain:
x25_queue_rx_frame returns 1
|
v
x25_state3_machine receives the return value 1 and takes the else
branch at line 278, setting queued=0 and returning 0
|
v
x25_process_rx_frame returns queued=0
|
v
x25_backlog_rcv at line 452 sees queued=0 and calls kfree_skb(skb)
again
This would free the same skb twice. Looking at x25_backlog_rcv:
net/x25/x25_in.c:x25_backlog_rcv() {
...
queued = x25_process_rx_frame(sk, skb);
...
if (!queued)
kfree_skb(skb);
}5dCVE-2018-109027.8 HIG40.9%
——12It was found that the raw midi kernel driver does not protect against concurrent access which leads to a double realloc (double free) in snd_rawmidi_input_params() and snd_rawmidi_output_status() which are part of snd_rawmidi_ioctl() handler in rawmidi.c file. A malicious local attacker could possibly use this for privilege escalation.12d