CVE WatchJul 24, 2026

CVE-2026-66033

libssh2 through 1.11.1, fixed in commit a2ed82d, contains a pre-authentication integer underflow vulnerability in the ssh2_cipher_crypt() fu

CVSS

7.5

High

EPSS

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KEV

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Exploit Today

0-100

Published: Jul 24, 2026 · Last modified: Jul 24, 2026 · CWE-125 · CWE-191

EPSS · 30d

Not enough EPSS history yet.

Technical description

libssh2 through 1.11.1, fixed in commit a2ed82d, contains a pre-authentication integer underflow vulnerability in the ssh2_cipher_crypt() function in src/openssl.c that allows a malicious SSH server to crash any connecting client by negotiating AES-GCM ciphers during handshake. Attackers can exploit the underflow in the expression computing blocksize minus aadlen minus authentication tag length to trigger an out-of-bounds read and a memcpy call with a near-SIZE_MAX length argument, causing immediate process crash before any authentication occurs.

Official references

Related CVEs

CVECVSSEPSSKEVRExploitTitleMod.

CVE-2026-663376.5 MED

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——0A flaw was found in libsoup. An unsigned integer underflow in the soup_filter_input_stream_read_until() function causes a heap buffer over-read when parsing multipart HTTP responses. A malicious HTTP server can exploit this by sending a crafted multipart response, potentially causing the client application to crash or disclose sensitive heap memory.16h CVE-2026-660347.5 HIG

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——0libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability that allows a malicious SSH server to trigger an arbitrary-length heap out-of-bounds read and a free of an uninitialized pointer via the publickey subsystem. In libssh2_publickey_list_fetch(), the version 1 response parser reads a server-controlled comment_len value and advances the parse pointer without verifying sufficient bytes remain in the buffer, causing the out-of-bounds read to leak heap pointers from adjacent allocations defeating ASLR, followed by heap allocator state corruption when the error cleanup path frees an uninitialized pointer from a non-zeroed realloc() region.10h CVE-2026-55732—

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——0Out-of-bounds Read (CWE-125) in BACnet packet parsing (`bacdt_datetime_to_tod`) in Loytec LIP-ME201C, L-INX, L-GATE, L-ROC, L-IOB, L-DALI, L-VIS and L-PAD through 8.4.18 on LINX-A64 allows an unauthenticated remote attacker to crash `linx_a64.exe` and ultimately reboot the device via a malformed BACnet TimeSynchronization or UTC-TimeSynchronization packet with an invalid month value. The same vulnerability affects multiple other Loytec products.1d CVE-2026-458138.8 HIG

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——0Out-of-bounds Write, Integer Underflow (Wrap or Wraparound) vulnerability in Apache NimBLE BASS service. Improper validation when parsing BASS service "Add Source" and "Modify Source" operation PDU could results in stack buffer overflow or arbitrary out-of-bound read. This can be triggered by nearby devices over Bluetooth connection, however pairing is required prior to accessing BASS service, which depending on device configuration may or may not require user action. This issue affects Apache NimBLE: through 1.9.0. Users are recommended to upgrade to version 1.10.0, which fixes the issue.18h CVE-2026-56391—

3.3%

——1GNU coreutils uniq is vulnerable to an out‑of‑bounds read due to incorrect handling of multibyte input when the -w (--check-chars) option is used. The find_field() function miscalculates the byte length of characters by repeatedly processing a fixed pointer instead of advancing through the input, resulting in an inflated length value. This incorrect length is later used in a memcmp operation, causing reads beyond the allocated buffer when processing crafted multibyte input. When running GNU coreutils uniq with attacker-provided arguments, this behavior leads to a crash and potential adjacent heap memory exposure. This issue has been fixed in the commit d64e35a8a4c0e4608321433e0d84d917e4e36371.1d CVE-2026-160028.2 HIG

17.3%

——5The affected product is vulnerable to an Out-of-bounds read, which may allow an attacker to crash the parsing process and cause a denial of service.1d