How severe is CVE-2026-55211?

CVE-2026-55211 has a CVSS score of 9.8/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2026-55211?

CVE-2026-55211 affects the following packages: surfio (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2026-55211?

Update surfio to 0.0.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55211 is resolved across your whole dependency graph.

How do I detect CVE-2026-55211 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for surfio. 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-2026-55211 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-2026-55211?

O3 pinpoints whether CVE-2026-55211 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-2026-55211 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-55211 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.

When was CVE-2026-55211 published, and has it been updated?

CVE-2026-55211 was published on August 18, 2026 and was last updated on August 19, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

CRITICAL severity

CVE-2026-55211

CRITICALFix: equinor/surfio#86

CVE-2026-55211 is a critical-severity (CVSS 9.8) remote code execution vulnerability in surfio. O3 Security confirms whether CVE-2026-55211 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

surfio has an out-of-bounds read

Also known asPYSEC-2026-3701

Published

Aug 18, 2026

Updated

Aug 19, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Aug 19, 2026 · OSV.dev, FIRST.org (EPSS)

Real-World Exposure

1 pkg affected

🐍surfio

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

Impact

Prior to version 0.0.19, surfio would not correctly validate size fields in irap files, leading to a buffer overflow . The severity rating assumes that surfio is used to parse untrused files in a networking context such as a web service.

Patches

The bug has been patched in version 0.0.19

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`surfio`	all versions	0.0.19

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for surfio. 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 surfio to 0.0.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55211 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-2026-55211 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-2026-55211. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact Prior to version 0.0.19, surfio would not correctly validate size fields in irap files, leading to a buffer overflow . The severity rating assumes that surfio is used to parse untrused files in a networking context such as a web service. ### Patches The bug has been patched in version 0.0.19

O3 Security · Impact-Aware SCA

Is CVE-2026-55211 in your dependencies?

O3 detects CVE-2026-55211 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works