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CVE-2020-4042

Authentication bypass in Bareos

6.8 MediumFix available

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

0.97%Up 0.3 points since Apr 14, 2021
90%50%10%1%

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 MediumCVSS: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 MediumCVSS: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 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
CVSS 2.0
4.3 MediumAV: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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

Affected packages
PackageAffectedFixed
bareos
Alpine:v3.13
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.14
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.15
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.16
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.17
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.18
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.19
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.20
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.21
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.22
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.23
before 19.2.8-r0
19.2.8-r0
bareos
Alpine:v3.24
before 19.2.8-r0
19.2.8-r0
bareos
Ubuntu: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

History
RecordedChangedSources
affected, aliases, facts, referencesOSV
aliasesEUVD
first indexedCVE 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.

References

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