How severe is CVE-2026-28681?

CVE-2026-28681 has a CVSS score of 8.1/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-28681?

CVE-2026-28681 affects the following packages: irrd (PyPI), irrd (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-28681?

Update irrd to 4.4.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28681 is resolved across your whole dependency graph.

How do I detect CVE-2026-28681 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for irrd. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-28681 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-28681?

O3 pinpoints whether CVE-2026-28681 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-28681 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-28681 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-28681?

CVE-2026-28681 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 34th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

When was CVE-2026-28681 published, and has it been updated?

CVE-2026-28681 was published on March 6, 2026 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2026-28681: irrd (High 8.1)

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk34th percentile+0.39%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

2 pkgs affected

🐍irrd🐍irrd

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

Internet Routing Registry daemon version 4 is an IRR database server, processing IRR objects in the RPSL format. From version 4.4.0 to before version 4.4.5 and from version 4.5.0 to before version 4.5.1, an attacker can manipulate the HTTP Host header on a password reset or account creation request. The confirmation link in the resulting email can then point to an attacker-controlled domain. Opening the link in the email is sufficient to pass the token to the attacker, who can then use it on the real IRRD instance to take over the account. A compromised account can then be used to modify RPSL objects maintained by the account's mntners and perform other account actions. If the user had two-factor authentication configured, which is required for users with override access, an attacker is not able to log in, even after successfully resetting the password. This issue has been patched in versions 4.4.5 and 4.5.1.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`irrd`	≥ 4.4.0&&< 4.4.5	4.4.5
🐍PyPI	`irrd`	≥ 4.5.0&&< 4.5.1	4.5.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for irrd. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update irrd to 4.4.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-28681 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-28681 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-28681. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Internet Routing Registry daemon version 4 is an IRR database server, processing IRR objects in the RPSL format. From version 4.4.0 to before version 4.4.5 and from version 4.5.0 to before version 4.5.1, an attacker can manipulate the HTTP Host header on a password reset or account creation request. The confirmation link in the resulting email can then point to an attacker-controlled domain. Opening the link in the email is sufficient to pass the token to the attacker, who can then use it on the real IRRD instance to take over the account. A compromised account can then be used to modify RPSL

O3 Security · Impact-Aware SCA

Is CVE-2026-28681 in your dependencies?

O3 detects CVE-2026-28681 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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CVE-2026-28681