CVE-2020-4042
Authentication bypass in Bareos
Bareos before version 19.2.8 and earlier allows a malicious client to communicate with the director without knowledge of the shared secret if the director allows client initiated connection and connects to the client itself. The malicious client can replay the Bareos director's cram-md5 challenge to the director itself leading to the director responding to the replayed challenge. The response obtained is then a valid reply to the directors original challenge. This is fixed in version 19.2.8.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
6.8
Authentication bypass in Bareos
Bareos before version 19.2.8 and earlier allows a malicious client to communicate with the director without knowledge of the shared secret if the director allows client initiated connection and connects to the client itself. The malicious client can replay the Bareos director's cram-md5 challenge to the director itself leading to the director responding to the replayed challenge. The response obtained is then a valid reply to the directors original challenge. This is fixed in version 19.2.8.
- Record
CVE-2020-4042- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N - Weakness
- CWE-294
- Updated
- 2026-11-02
EUVDEUVD-2020-25302
6.8
Bareos before version 19.2.8 and earlier allows a malicious client to communicate with the director without knowledge of the shared secret if the director allows client initiated connection and connects to the client itself. The malicious client can replay the Bareos director's cram-md5 challenge to the director itself leading to the director responding to the replayed challenge. The response obtained is then a valid reply to the directors original challenge. This is fixed in version 19.2.8.
- Record
EUVD-2020-25302- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-03
NVD
6.8
Bareos before version 19.2.8 and earlier allows a malicious client to communicate with the director without knowledge of the shared secret if the director allows client initiated connection and connects to the client itself. The malicious client can replay the Bareos director's cram-md5 challenge to the director itself leading to the director responding to the replayed challenge. The response obtained is then a valid reply to the directors original challenge. This is fixed in version 19.2.8.
- Record
CVE-2020-4042- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N - CVSS 2.0
- 4.3 Medium
AV:N/AC:M/Au:N/C:N/I:P/A:N - Weakness
- CWE-294
- Updated
- 2026-11-02
OSVALPINE-CVE-2020-4042
6.8
Bareos before version 19.2.8 and earlier allows a malicious client to communicate with the director without knowledge of the shared secret if the director allows client initiated connection and connects to the client itself. The malicious client can replay the Bareos director's cram-md5 challenge to the director itself leading to the director responding to the replayed challenge. The response obtained is then a valid reply to the directors original challenge. This is fixed in version 19.2.8.
- Record
ALPINE-CVE-2020-4042- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-03
OSV
6.8
Bareos before version 19.2.8 and earlier allows a malicious client to communicate with the director without knowledge of the shared secret if the director allows client initiated connection and connects to the client itself. The malicious client can replay the Bareos director's cram-md5 challenge to the director itself leading to the director responding to the replayed challenge. The response obtained is then a valid reply to the directors original challenge. This is fixed in version 19.2.8.
- Record
CVE-2020-4042- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2020-4042
6.8
Bareos before version 19.2.8 and earlier allows a malicious client to communicate with the director without knowledge of the shared secret if the director allows client initiated connection and connects to the client itself. The malicious client can replay the Bareos director's cram-md5 challenge to the director itself leading to the director responding to the replayed challenge. The response obtained is then a valid reply to the directors original challenge. This is fixed in version 19.2.8.
- Record
UBUNTU-CVE-2020-4042- CVSS 3.1
- 6.8 Medium
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
bareosAlpine:v3.13 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.14 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.15 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.16 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.17 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.18 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.19 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.20 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.21 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.22 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.23 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosAlpine:v3.24 |
before 19.2.8-r0 | 19.2.8-r0 |
bareosUbuntu:16.04:LTS |
All versions, plus listed versions 14.2.5-114.2.5-214.2.6-114.2.6-214.2.6-2build114.2.6-3 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, aliases, facts, references | OSV | |
| aliases | EUVD | |
| first indexed | CVE List, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-4042 is a medium vulnerability (CVSS 6.8) in Bareos, published July 10, 2020. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.97%, the 62nd percentile. Fixed in bareos 19.2.8-r0.