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🛡️ CVE-2026-48028 — mastodon

🟡 CVSS 6.5 — Medium ✅ No Known Exploit NVD
6.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Mastodon: Removal of integrity-protected JSON entries from signed activities

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activities from a certain class of spoofing, allowing threat actors to remove JSON entries from valid signed activities from a third-party actor. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity low, availability low.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: None.
  • Integrity impact: Low — limited, and the attacker does not choose what is affected.
  • Availability impact: Low — limited, and the attacker does not choose what is affected.

Affected software

CVE-2026-48028 is recorded against 2 packages.

  • mastodon
  • unknown

Timeline and source

Published on 6 July 2026 and last revised on 8 July 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
nvd.nist.gov (Web)

Other advisories for this package

mastodon has other advisories on record. If you are patching this one, these are worth checking on the same host:

Details

Severity MEDIUM
CVSS Score 6.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L
CWE N/A
Public Exploit ✅ No
Source NVD
Published 2026-07-06
Updated 2026-08-20
Modified 2026-07-08
Fix URL N/A

Affected Packages

Software From version Fixed in
mastodon
unknown

Similar Threats

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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