CVE-2026-54088: File Browser: Command Injection via… (CVSS 9.3)

CVE List Score used 9.3

File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE)

File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. Prior to 2.63.6, the Hook Authentication feature in File Browser allows administrators to delegate login verification to an external shell command. User-supplied credentials (username and password) are interpolated into this command string using os.Expand without sanitization. An unauthenticated remote attacker can inject shell metacharacters in the username or password field at the login screen, causing the server to execute arbitrary OS commands before any authentication takes place. This is a critical pre-authentication RCE. This vulnerability is fixed in 2.63.6.

Record: CVE-2026-54088
CVSS 4.0: 9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness: CWE-78, CWE-88, CWE-306
Updated: 2026-11-02

EUVDEUVD-2026-39510 9.3

File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. Prior to 2.63.6, the Hook Authentication feature in File Browser allows administrators to delegate login verification to an external shell command. User-supplied credentials (username and password) are interpolated into this command string using os.Expand without sanitization. An unauthenticated remote attacker can inject shell metacharacters in the username or password field at the login screen, causing the server to execute arbitrary OS commands before any authentication takes place. This is a critical pre-authentication RCE. This vulnerability is fixed in 2.63.6.

Record: EUVD-2026-39510
CVSS 4.0: 9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-m93h-4hw7-5qcm 9.3

File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE)

Overview

The Hook Authentication feature in File Browser allows administrators to delegate login verification to an external shell command. User-supplied credentials (username and password) are interpolated into this command string using os.Expand without sanitization. An unauthenticated remote attacker can inject shell metacharacters in the username or password field at the login screen, causing the server to execute arbitrary OS commands before any authentication takes place. This is a critical pre-authentication RCE.

Affected Location

File: auth/hook.go
Function: HookAuth.RunCommand

CVSS v4.0

| Metric | Value | Rationale | |---|---|---| | Attack Vector (AV) | Network (N) | Exploitable via the login endpoint over HTTP from any network | | Attack Complexity (AC) | Low (L) | Single crafted HTTP request; no preparation needed | | Attack Requirements (AT) | None (N) | No race condition or special timing required | | Privileges Required (PR) | None (N) | No account required — pre-authentication attack | | User Interaction (UI) | None (N) | Fully automated; no victim action needed | | Vulnerable System Confidentiality (VC) | High (H) | Full read access to server filesystem and env | | Vulnerable System Integrity (VI) | High (H) | Arbitrary file write/modification | | Vulnerable System Availability (VA) | High (H) | Can kill processes, exhaust resources | | Subsequent System Confidentiality (SC) | None (N) | No direct impact on downstream systems assumed | | Subsequent System Integrity (SI) | None (N) | — | | Subsequent System Availability (SA) | None (N) | — |

Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N Base Score: 9.3 (Critical)

Note: PR:None is the critical differentiator from vulnerabilities 01 and 02. Because the injection point is the unauthenticated login endpoint, no account or session is required. A single HTTP request to the login API is sufficient to achieve RCE.

CWE

| ID | Name | Role | |---|---|---| | CWE-78 | Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') | Primary — attacker-supplied credentials embedded in shell command string via os.Expand | | CWE-88 | Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') | Secondary — $USERNAME/$PASSWORD expansion injects additional shell commands | | CWE-306 | Missing Authentication for Critical Function | Secondary — OS command execution is reachable before any authentication is verified |

Technical Details

HookAuth.RunCommand builds the authentication command and substitutes credential values using os.Expand:

// auth/hook.go
envMapping := func(key string) string {
    switch key {
    case "USERNAME":
        return a.Cred.Username  // directly from the HTTP login request body
    case "PASSWORD":
        return a.Cred.Password  // directly from the HTTP login request body
    default:
        return os.Getenv(key)
    }
}

for i, arg := range command {
    if i == 0 { continue }
    command[i] = os.Expand(arg, envMapping) // no escaping applied
}

os.Expand performs plain text substitution. There is no escaping, quoting, or validation of the credential values before they are embedded into the command string.

If an admin has configured the hook authentication command as:

sh -c "test $USERNAME = 'admin'"

...and an attacker submits the username ; id # at the login screen, the expanded command becomes:

sh -c "test ; id # = 'admin'"

The ; terminates the test expression and the shell executes id. The # comments out the remainder, preventing a syntax error. The attacker's command runs with the privileges of the File Browser process — without needing a valid account or password. …

Record: GHSA-m93h-4hw7-5qcm
CVSS 4.0: 9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness: CWE-78, CWE-88, CWE-306
Updated: 2026-11-02

NVD 9.3

File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. Prior to 2.63.6, the Hook Authentication feature in File Browser allows administrators to delegate login verification to an external shell command. User-supplied credentials (username and password) are interpolated into this command string using os.Expand without sanitization. An unauthenticated remote attacker can inject shell metacharacters in the username or password field at the login screen, causing the server to execute arbitrary OS commands before any authentication takes place. This is a critical pre-authentication RCE. This vulnerability is fixed in 2.63.6.

Record: CVE-2026-54088
CVSS 4.0: 9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Weakness: CWE-78, CWE-88, CWE-306
Updated: 2026-11-02

OSV 9.3

File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE)

File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. Prior to 2.63.6, the Hook Authentication feature in File Browser allows administrators to delegate login verification to an external shell command. User-supplied credentials (username and password) are interpolated into this command string using os.Expand without sanitization. An unauthenticated remote attacker can inject shell metacharacters in the username or password field at the login screen, causing the server to execute arbitrary OS commands before any authentication takes place. This is a critical pre-authentication RCE. This vulnerability is fixed in 2.63.6.

Record: CVE-2026-54088
CVSS 4.0: 9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness: CWE-306, CWE-78, CWE-88
Updated: 2026-11-02

OSVGHSA-m93h-4hw7-5qcm 9.3

File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE)

Overview

The Hook Authentication feature in File Browser allows administrators to delegate login verification to an external shell command. User-supplied credentials (username and password) are interpolated into this command string using os.Expand without sanitization. An unauthenticated remote attacker can inject shell metacharacters in the username or password field at the login screen, causing the server to execute arbitrary OS commands before any authentication takes place. This is a critical pre-authentication RCE.

Affected Location

File: auth/hook.go
Function: HookAuth.RunCommand

CVSS v4.0

| Metric | Value | Rationale | |---|---|---| | Attack Vector (AV) | Network (N) | Exploitable via the login endpoint over HTTP from any network | | Attack Complexity (AC) | Low (L) | Single crafted HTTP request; no preparation needed | | Attack Requirements (AT) | None (N) | No race condition or special timing required | | Privileges Required (PR) | None (N) | No account required — pre-authentication attack | | User Interaction (UI) | None (N) | Fully automated; no victim action needed | | Vulnerable System Confidentiality (VC) | High (H) | Full read access to server filesystem and env | | Vulnerable System Integrity (VI) | High (H) | Arbitrary file write/modification | | Vulnerable System Availability (VA) | High (H) | Can kill processes, exhaust resources | | Subsequent System Confidentiality (SC) | None (N) | No direct impact on downstream systems assumed | | Subsequent System Integrity (SI) | None (N) | — | | Subsequent System Availability (SA) | None (N) | — |

Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N Base Score: 9.3 (Critical)

Note: PR:None is the critical differentiator from vulnerabilities 01 and 02. Because the injection point is the unauthenticated login endpoint, no account or session is required. A single HTTP request to the login API is sufficient to achieve RCE.

CWE

| ID | Name | Role | |---|---|---| | CWE-78 | Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') | Primary — attacker-supplied credentials embedded in shell command string via os.Expand | | CWE-88 | Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') | Secondary — $USERNAME/$PASSWORD expansion injects additional shell commands | | CWE-306 | Missing Authentication for Critical Function | Secondary — OS command execution is reachable before any authentication is verified |

Technical Details

HookAuth.RunCommand builds the authentication command and substitutes credential values using os.Expand:

// auth/hook.go
envMapping := func(key string) string {
    switch key {
    case "USERNAME":
        return a.Cred.Username  // directly from the HTTP login request body
    case "PASSWORD":
        return a.Cred.Password  // directly from the HTTP login request body
    default:
        return os.Getenv(key)
    }
}

for i, arg := range command {
    if i == 0 { continue }
    command[i] = os.Expand(arg, envMapping) // no escaping applied
}

os.Expand performs plain text substitution. There is no escaping, quoting, or validation of the credential values before they are embedded into the command string.

If an admin has configured the hook authentication command as:

sh -c "test $USERNAME = 'admin'"

...and an attacker submits the username ; id # at the login screen, the expanded command becomes:

sh -c "test ; id # = 'admin'"

The ; terminates the test expression and the shell executes id. The # comments out the remainder, preventing a syntax error. The attacker's command runs with the privileges of the File Browser process — without needing a valid account or password. …

Record: GHSA-m93h-4hw7-5qcm
CVSS 4.0: 9.3 CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness: CWE-306, CWE-78, CWE-88
Updated: 2026-11-02

OSVGO-2026-5962 No score

File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE) in github.com/filebrowser/filebrowser

File Browser: Command Injection via Authentication Hook Shell Substitution (Pre-Authentication RCE) in github.com/filebrowser/filebrowser

Record: GO-2026-5962
Updated: 2026-11-02

OSVopenSUSE-SU-2026:21483-1 No score

Security update for govulncheck-vulndb

This update for govulncheck-vulndb fixes the following issues:

Update to version 0.0.20260723T184607 2026-07-23T18:46:07Z (jsc#PED-11136).

Go CVE Numbering Authority IDs added or updated with aliases:

GO-2026-4730 CVE-2026-33022 GHSA-cv4x-93xx-wgfj
GO-2026-4761 CVE-2026-33211 GHSA-j5q5-j9gm-2w5c
GO-2026-5102 CVE-2026-45021 GHSA-3vcp-chfh-f6r2
GO-2026-5272 CVE-2026-40938 GHSA-94jr-7pqp-xhcq
GO-2026-5486 CVE-2026-40924 GHSA-m2cx-gpqf-qf74
GO-2026-5542 CVE-2026-40090 GHSA-pj97-4p9w-gx3q
GO-2026-5630 CVE-2026-25542 GHSA-rmx9-2pp3-xhcr
GO-2026-5643 CVE-2026-40923 GHSA-rx35-6rhx-7858
GO-2026-5675 CVE-2026-41492 GHSA-vvf7-6rmr-m29q
GO-2026-5711 CVE-2026-40161 GHSA-wjxp-xrpv-xpff
GO-2026-5746 CVE-2026-41567 GHSA-x86f-5xw2-fm2r
GO-2026-5749 CVE-2026-41328 GHSA-x92x-px7w-4gx4
GO-2026-5837 CVE-2026-44840 GHSA-q2m9-6jp9-c6mc
GO-2026-5929 CVE-2026-44342 GHSA-26v7-h57m-gh9m
GO-2026-5930 CVE-2026-33655 GHSA-6qcr-qxgr-m7fv
GO-2026-5933 GHSA-3g4q-2f67-2gvh
GO-2026-5934 GHSA-59qp-cfj3-rp64
GO-2026-5935 GHSA-7856-g3gv-9wq8
GO-2026-5936 CVE-2026-53552 GHSA-26rh-24rg-j3vv
GO-2026-5937 CVE-2026-53508 GHSA-2jcc-mxv7-p3f9
GO-2026-5938 CVE-2026-53553 GHSA-4g5x-hcwm-82jw
GO-2026-5939 CVE-2026-10517 GHSA-698x-9w2p-7vvp
GO-2026-5940 CVE-2026-53572 GHSA-6w3m-4hhp-775q
GO-2026-5941 CVE-2026-53487 GHSA-gvhc-wv3v-7pf8
GO-2026-5942 CVE-2026-46600
GO-2026-5944 CVE-2026-50197 GHSA-659f-rgp5-w4wf
GO-2026-5945 CVE-2026-6815 GHSA-rmxx-v9rj-vpvg
GO-2026-5946 CVE-2026-52831 GHSA-v5px-423j-pf7p
GO-2026-5947 CVE-2026-53649 GHSA-xqhv-chqm-fhcc
GO-2026-5948 CVE-2026-50554 GHSA-588f-fvcv-xhvf
GO-2026-5949 CVE-2026-50553 GHSA-rqrh-8wpv-x7hh
GO-2026-5950 CVE-2026-53602 GHSA-339v-266x-79xr
GO-2026-5951 CVE-2026-10219 GHSA-6jm8-4fhr-5w64
GO-2026-5952 CVE-2026-49834 GHSA-9vcr-p3rj-q5q6
GO-2026-5953 CVE-2026-9094 GHSA-c9w5-qp6m-m395
GO-2026-5956 CVE-2026-55252 GHSA-h5g6-xmh4-hc37
GO-2026-5957 CVE-2026-54158 GHSA-5xfx-xj4h-5p7r
GO-2026-5958 CVE-2026-54068 GHSA-gcm7-57gf-953c
GO-2026-5959 CVE-2026-54072 GHSA-h29v-hj44-q8cv
GO-2026-5961 CVE-2026-54069 GHSA-hvr9-72v2-fff3
GO-2026-5962 CVE-2026-54088 GHSA-m93h-4hw7-5qcm
GO-2026-5963 CVE-2026-54067 GHSA-mvjr-vv3c-w4qv
GO-2026-5964 CVE-2026-54066 GHSA-p4m3-mgmm-c664
GO-2026-5965 CVE-2026-54070 GHSA-w7cg-whh7-xp28
GO-2026-5966 CVE-2026-54089 GHSA-xqp3-jq6g-x3qm
GO-2026-5967 CVE-2026-50551 GHSA-56mp-4f3v-fgj2
GO-2026-5968 CVE-2026-54174 GHSA-fpg8-7664-jc5q
GO-2026-5969 GHSA-g936-7jqj-mwv8
GO-2026-5970 CVE-2026-56852
GO-2026-5973 CVE-2026-54250 GHSA-jxr7-mqhw-9p98
GO-2026-5974 CVE-2026-44300 GHSA-wmj8-9953-vff5
GO-2026-5975 CVE-2026-50018 GHSA-42j2-w334-qxw7
GO-2026-5976 CVE-2026-50141 GHSA-g7mm-9vx7-jm7h
GO-2026-5977 CVE-2026-50013 GHSA-qrh4-p6v4-mrfg
GO-2026-5978 CVE-2026-50125 GHSA-qw5r-ppcg-f8rj
GO-2026-5979 CVE-2026-50006 GHSA-xrcf-6jh3-ggvx
GO-2026-5980 CVE-2026-50158 GHSA-2c7f-fxww-6w6c
GO-2026-5981 GHSA-mqxv-9rm6-w8qc
GO-2026-5982 GHSA-pqg7-v6wh-3pfp
GO-2026-5984 CVE-2026-53604 GHSA-2p2f-px33-4vv5
GO-2026-5985 GHSA-7rx3-5wx3-5v76
GO-2026-5986 CVE-2026-61699 GHSA-cm26-5974-52h8
GO-2026-5987 CVE-2026-55513 GHSA-g4x6-jcvr-9m3g
GO-2026-5988 CVE-2026-54628 GHSA-hwrq-8wxh-q4xv
GO-2026-5989 CVE-2026-55512 GHSA-m3cx-mwpg-32jg
GO-2026-5990 CVE-2026-54629 GHSA-mf78-3rpf-r784
GO-2026-5991 CVE-2026-53603 GHSA-q4vm-pq3q-8wgq
GO-2026-5992 CVE-2026-61549 GHSA-qf34-295c-26v8
GO-2026-5996 CVE-2026-54450 GHSA-pph6-vfjv-vpjw
GO-2026-5997 CVE-2026-54452 GHSA-xgch-x3mx-cm3c
GO-2026-5998 CVE-2026-54495 GHSA-398h-7f66-3h4p
GO-2026-5999 CVE-2026-10814 GHSA-jh6h-v6mp-h22v
GO-2026-6002 CVE-2026-58196 GHSA-pr64-jmmf-jp54
GO-2026-6003 CVE-2026-53714 GHSA-22xc-xg2r-9j7v
GO-2026-6004 CVE-2026-52833 GHSA-3v79-m2cg-89ww
GO-2026-6005 CVE-2026-53715 GHSA-8fv2-88gg-hm7q
GO-2026-6006 CVE-2026-53716 GHSA-cxpq-8v7q-cg56 *…

Record: openSUSE-SU-2026:21483-1
Updated: 2026-11-02

Package	Affected	Fixed
`github.com/filebrowser/filebrowser/v2` Go	through 2.63.5	2.63.6
`github.com/filebrowser/filebrowser/v2` Go	before 2.63.6	2.63.6
`github.com/filebrowser/filebrowser` Go	All versions	None known
`govulncheck-vulndb` openSUSE:Leap 16.0 From an advisory covering 1734 CVEs	before 0.0.20260723T184607-160000.1.1	0.0.20260723T184607-160000.1.1

Recorded	Changed	Sources
Nov 6, 2026	affected, facts
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub

CVE-2026-54088

Attack profile

How easy it is to exploit

What an attacker can affect

Exploit likelihood

What each source reports

Overview

Affected Location

CVSS v4.0

CWE

Technical Details

Overview

Affected Location

CVSS v4.0

CWE

Technical Details

Affected products

Affected packages

Public exploits

History

In short

References