Answer in brief
CVE-2026-48028 records a Medium severity (CVSS 6.5) vulnerability in Mastodon: Removal of integrity-protected JSON entries from signed activities. The current sources do not mark it as known exploited. The current feed maps mastodon/mastodon (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps mastodon/mastodon (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| mastodon/mastodongeneric | >= 4.5.0-beta.1, < 4.5.10 || >= 4.4.0-beta.1, < 4.4.17 || < 4.3.23 | Not reported |
Published upstream
Jun 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 24, 2026
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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-48028 records a Medium severity (CVSS 6.5) vulnerability in Mastodon: Removal of integrity-protected JSON entries from signed activities. The current sources do not mark it as known exploited. The current feed maps mastodon/mastodon (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps mastodon/mastodon (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| mastodon/mastodongeneric | >= 4.5.0-beta.1, < 4.5.10 || >= 4.4.0-beta.1, < 4.4.17 || < 4.3.23 | Not reported |
Published upstream
Jun 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 24, 2026
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.
Quoted source text, attributed separately from HOL analysis.