CVE-2021-3882: LedgerSMB does not set the 'Secure' attribute on the session authorization cookie when the client uses HTTPS and the LedgerSMB server is behind a reve...

Description

LedgerSMB does not set the 'Secure' attribute on the session authorization cookie when the client uses HTTPS and the LedgerSMB server is behind a reverse proxy. By tricking a user to use an unencrypted connection (HTTP), an attacker may be able to obtain the authentication data by capturing network traffic. LedgerSMB 1.8 and newer switched from Basic authentication to using cookie authentication with encrypted cookies. Although an attacker can't access the information inside the cookie, nor the password of the user, possession of the cookie is enough to access the application as the user from which the cookie has been obtained. In order for the attacker to obtain the cookie, first of all the server must be configured to respond to unencrypted requests, the attacker must be suitably positioned to eavesdrop on the network traffic between the client and the server *and* the user must be tricked into using unencrypted HTTP traffic. Proper audit control and separation of duties limit Integrity impact of the attack vector. Users of LedgerSMB 1.8 are urged to upgrade to known-fixed versions. Users of LedgerSMB 1.7 or 1.9 are unaffected by this vulnerability and don't need to take action. As a workaround, users may configure their Apache or Nginx reverse proxy to add the Secure attribute at the network boundary instead of relying on LedgerSMB. For Apache, please refer to the 'Header always edit' configuration command in the mod_headers module. For Nginx, please refer to the 'proxy_cookie_flags' configuration command.

Metrics

CVSS 3.1

6.8/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS Probability

0.94%

56.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Ledgersmb	Ledgersmb	>= 1.8.0, < 1.8.22

References

https://github.com/ledgersmb/ledgersmb/commit/c242f5a2abf4b99b0da205473cbba034f306bfe2Patch, Third Party Advisory
https://huntr.dev/bounties/7061d97a-98a5-495a-8ba0-3a4c66091e9dExploit, Third Party Advisory
https://ledgersmb.org/cve-2021-3882-sensitive-non-secure-cookieBroken Link
https://github.com/ledgersmb/ledgersmb/commit/c242f5a2abf4b99b0da205473cbba034f306bfe2Patch, Third Party Advisory
https://huntr.dev/bounties/7061d97a-98a5-495a-8ba0-3a4c66091e9dExploit, Third Party Advisory
https://ledgersmb.org/cve-2021-3882-sensitive-non-secure-cookieBroken Link

Timeline

Published: Oct 14, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3882?

LedgerSMB does not set the 'Secure' attribute on the session authorization cookie when the client uses HTTPS and the LedgerSMB server is behind a reverse proxy. By tricking a user to use an unencrypted connection (HTTP), an attacker may be able to obtain the authentication data by capturing network traffic. LedgerSMB 1.8 and newer switched from Basic authentication to using cookie authentication with encrypted cookies. Although an attacker can't access the information inside the cookie, nor the password of the user, possession of the cookie is enough to access the application as the user from which the cookie has been obtained. In order for the attacker to obtain the cookie, first of all the server must be configured to respond to unencrypted requests, the attacker must be suitably positioned to eavesdrop on the network traffic between the client and the server *and* the user must be tricked into using unencrypted HTTP traffic. Proper audit control and separation of duties limit Integrity impact of the attack vector. Users of LedgerSMB 1.8 are urged to upgrade to known-fixed versions. Users of LedgerSMB 1.7 or 1.9 are unaffected by this vulnerability and don't need to take action. As a workaround, users may configure their Apache or Nginx reverse proxy to add the Secure attribute at the network boundary instead of relying on LedgerSMB. For Apache, please refer to the 'Header always edit' configuration command in the mod_headers module. For Nginx, please refer to the 'proxy_cookie_flags' configuration command.

How severe is CVE-2021-3882?

CVE-2021-3882 has a CVSS score of 6.8/10 (MEDIUM severity). The EPSS model estimates a 0.94% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3882?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

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