CVE-2023-3394Public exploitNetwork attack vector

Account hijacking via unreplaced session identifier

Published Jun 23, 2023 · Updated Nov 7, 2024

Session fixation in FOSSBilling before 0.5.1 allows remote attackers to hijack a user's authenticated session through a preset session ID. The login flow retains the existing session identifier after authentication, allowing an attacker to reuse an identifier known before the victim signs in. Exploitation requires the victim to authenticate with that fixed identifier, after which the attacker gains the victim's application access.

CVSS severity6.8
Medium
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Session fixation in FOSSBilling before 0.5.1 allows remote attackers to hijack a user's authenticated session through a preset session ID. The login flow retains the existing session identifier after authentication, allowing an attacker to reuse an identifier known before the victim signs in. Exploitation requires the victim to authenticate with that fixed identifier, after which the attacker gains the victim's application access.

The record

CVE
CVE-2023-3394
Published
Jun 23, 2023
Updated
Nov 7, 2024
Vendor
FOSSBilling
Product
FOSSBilling
Classifications
CWE-384, T1550.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 23, 2023CVE publishedPublication date reported by the CVE source.
  2. Nov 7, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <0.5.1
  2. Affected versionversion=unspecified <0.5.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

FOSSBilling · FOSSBillingversion=0 <0.5.1; version=unspecified <0.5.1

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
6.8huntr.devCVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-384Session Fixation
T1550.004Web Session Cookie

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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