Unrated

Pre-authentication DoS in Pomerium HPKE callback flow

IdentifiersCVE-2026-50285CWE-400

CVE-2026-50285 is a pre-authentication denial-of-service vulnerability in Pomerium affecting the HPKE callback flow used by stateless authentication deployments. The flaw arises because attacker-controlled zstd-compressed data supplied to the callback processing path is decompressed without an enforced output size limit. As a result, specially crafted HPKE-encrypted input can trigger unbounded memory allocation during decompression in the callback handling logic, enabling remote exhaustion of process memory before authentication is completed.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an unauthenticated remote attacker to consume excessive memory on the affected Pomerium instance, leading to severe resource exhaustion, degraded proxy performance, or process termination. The practical outcome is denial of service against applications and services protected by the affected deployment.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by avoiding the affected stateless or hosted authentication flow where operationally feasible, limiting external reachability to the callback endpoint, and applying request filtering, rate limiting, or WAF protections to constrain repeated malicious requests. Self-hosted stateful deployments are not affected based on the available information.

Remediation

Patch, then assume compromise.

Upgrade Pomerium to version 0.32.8 or later. The underlying fix is to enforce a decompressed output size limit in the vulnerable callback decoding path. Additional hardening includes validating the sender public key before attempting decompression.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

PomeriumPomeriumapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

No public activity tracked yet. Mallory keeps watching.

0 SOURCESView more in app

No public activity observed for this vulnerability.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity