CVE-2026-34148: Fedify is a TypeScript library for building federated server apps powered by ActivityPub

Q: How do I fix CVE-2026-34148?

fedify\/fedify: upgrade to 1.9.6, 1.10.5, 2.0.8, 2.1.1; fedify\/vocab-runtime: upgrade to 2.0.8, 2.1.1. Exact commands for each OS are on this page.

Q: Is CVE-2026-34148 being exploited?

CVE-2026-34148 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-34148 affect?

CVE-2026-34148 affects fedify\/fedify, fedify\/vocab-runtime. Severity is high (CVSS 7.5). Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Prior to 1.9.6, 1.10.5, 2.0.8, and 2.1.1, @fedify/fedify follows HTTP redirects recursively in its remote document loader and authenticated document l

Q: How urgent is CVE-2026-34148?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

HIGH 7.5REMOTEUPGRADEUPGRADE

CVE-2026-34148 is a high-severity flaw (CVSS 7.5) affecting fedify\/fedify, fedify\/vocab-runtime. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Prior to 1.9.6, 1.10.5, 2.0.8, and 2.1.1, @fedify/fedify follows HTTP redirects recursively in its remote document loader and authenticated document loader without enforcing a maximum redirect count or visited-URL loop detection. An attacker who controls a remote ActivityPub key or actor URL can force a server using Fedify to make repeated outbound requests

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 54%)
CISA exploited list	No
Weakness	CWE-400, CWE-770
Published	2026-04-06
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: fedify

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-06 16:16 UTCPublished CVE record published
2026-10-26 22:10 UTCUpdated Record last modified

fedify fedify\/fedify UPGRADE

Affected: < 1.9.6 · >= 1.10.0 and < 1.10.5 · >= 2.0.0 and < 2.0.8 · >= 2.1.0 and < 2.1.1

Fixed in: 1.9.6, 1.10.5, 2.0.8, 2.1.1

Safe to downgrade to: a release before 1.10.0

1. Check installed version

npm ls fedifyfedify

2. UPGRADE to 1.9.6

npm install fedifyfedify@">=1.9.6"

3. If no update is available yet, DOWNGRADE to a release before 1.10.0

npm view fedifyfedify versions npm install fedifyfedify@"<1.10.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

fedify fedify\/vocab-runtime UPGRADE

Affected: < 2.0.8 · >= 2.1.0 and < 2.1.1

Fixed in: 2.0.8, 2.1.1

Safe to downgrade to: a release before 2.1.0

1. Check installed version

npm ls fedifyvocab-runtime

2. UPGRADE to 2.0.8

npm install fedifyvocab-runtime@">=2.0.8"

3. If no update is available yet, DOWNGRADE to a release before 2.1.0

npm view fedifyvocab-runtime versions npm install fedifyvocab-runtime@"<2.1.0"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-34148?

fedify\/fedify: upgrade to 1.9.6, 1.10.5, 2.0.8, 2.1.1; fedify\/vocab-runtime: upgrade to 2.0.8, 2.1.1. Exact commands for each OS are on this page.

Is CVE-2026-34148 being exploited?

CVE-2026-34148 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-34148 affect?

CVE-2026-34148 affects fedify\/fedify, fedify\/vocab-runtime. Severity is high (CVSS 7.5). Fedify is a TypeScript library for building federated server apps powered by ActivityPub. Prior to 1.9.6, 1.10.5, 2.0.8, and 2.1.1, @fedify/fedify follows HTTP redirects recursively in its remote document loader and authenticated document l

How urgent is CVE-2026-34148?

Priority 48/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

References

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