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Vulnerability details: VCID-jw8s-ztzj-xqc2
Vulnerability ID VCID-jw8s-ztzj-xqc2
Aliases CVE-2025-54804
GHSA-h5rc-j5f5-3gcm
Summary russh is missing overflow checks during channel windows adjust ### Summary The channel window adjust message of the SSH protocol is used to track the free space in the receive buffer of the other side of a channel. The current implementation takes the value from the message and adds it to an internal state value. This can result in a integer overflow. If the Rust code is compiled with overflow checks, it will panic. A malicious client can crash a server. ### Details According https://datatracker.ietf.org/doc/html/rfc4254#section-5.2, The value must not overflow. The incorrect handling is done in server/encrypted.rs and client/encrypted.rs in the handling of CHANNEL_WINDOW_ADJUST. ``` let amount = map_err!(u32::decode(&mut r))?; ... channel.recipient_window_size += amount; ``` It could be replaced with something like ``` if let Some(ref mut channel) = enc.channels.get_mut(&channel_num) { // rfc 4254: The window MUST NOT be increased above 2^32 - 1 bytes. new_size = channel.recipient_window_size.saturating_add(amount); channel.recipient_window_size = new_size; } ... ``` ### PoC A customized client code would be required to send a message with a big value like u32_max. Not done yet. ### Impact This problem seems only critical to a server. One user can crash the server, which might take down the service. A malicious server could also crash a single client, but this seems not very critical.
Status Published
Exploitability None
Weighted Severity None
Risk None
Affected and Fixed Packages Package Details
Weaknesses (1)
System Score Found at
cvssv3 6.5 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2025-54804.json
epss 0.0004 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.0004 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.0004 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.0004 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.0004 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.0004 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00044 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00044 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00044 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00047 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00047 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00047 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00047 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
epss 0.00054 https://api.first.org/data/v1/epss?cve=CVE-2025-54804
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-h5rc-j5f5-3gcm
cvssv3.1 6.5 https://github.com/Eugeny/russh
generic_textual MODERATE https://github.com/Eugeny/russh
cvssv3.1 6.5 https://github.com/Eugeny/russh/commit/0eb5e406780890e21ff71dd25d731b30676478e5
generic_textual MODERATE https://github.com/Eugeny/russh/commit/0eb5e406780890e21ff71dd25d731b30676478e5
ssvc Track https://github.com/Eugeny/russh/commit/0eb5e406780890e21ff71dd25d731b30676478e5
cvssv3.1 6.5 https://github.com/Eugeny/russh/security/advisories/GHSA-h5rc-j5f5-3gcm
cvssv3.1_qr MODERATE https://github.com/Eugeny/russh/security/advisories/GHSA-h5rc-j5f5-3gcm
generic_textual MODERATE https://github.com/Eugeny/russh/security/advisories/GHSA-h5rc-j5f5-3gcm
ssvc Track https://github.com/Eugeny/russh/security/advisories/GHSA-h5rc-j5f5-3gcm
cvssv3.1 6.5 https://nvd.nist.gov/vuln/detail/CVE-2025-54804
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2025-54804
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2025-54804.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

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none

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low

none

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low

none

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/Eugeny/russh
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/Eugeny/russh/commit/0eb5e406780890e21ff71dd25d731b30676478e5
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none


Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2025-08-05T14:44:02Z/ Found at https://github.com/Eugeny/russh/commit/0eb5e406780890e21ff71dd25d731b30676478e5
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://github.com/Eugeny/russh/security/advisories/GHSA-h5rc-j5f5-3gcm
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none


Vector: SSVCv2/E:P/A:N/T:P/P:M/B:A/M:M/D:T/2025-08-05T14:44:02Z/ Found at https://github.com/Eugeny/russh/security/advisories/GHSA-h5rc-j5f5-3gcm
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2025-54804
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none

Exploit Prediction Scoring System (EPSS)
Percentile 0.10889
EPSS Score 0.0004
Published At Aug. 5, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-08-05T09:27:32.431450+00:00 GithubOSV Importer Import https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/08/GHSA-h5rc-j5f5-3gcm/GHSA-h5rc-j5f5-3gcm.json 37.0.0