Unbounded Memory Growth in the OpenSSL QUIC PATH_CHALLENGE Handler
CVE-2026-34183 is a denial-of-service vulnerability in the OpenSSL integrated QUIC stack. A malicious remote QUIC peer can exhaust heap memory by flooding a QUIC client or server with packets containing PATH_CHALLENGE frames. For each received PATH_CHALLENGE, the local QUIC stack allocates a corresponding PATH_RESPONSE frame. That PATH_RESPONSE allocation is only freed after the remote peer acknowledges receipt of the PATH_RESPONSE. A malicious peer can intentionally avoid acknowledging those responses, causing unbounded accumulation of allocated PATH_RESPONSE frames and resulting in uncontrolled heap growth. The issue affects OpenSSL QUIC implementations, including affected branches noted in the supporting content: 4.0.0 before 4.0.1, 3.6.0 before 3.6.3, 3.5.0 before 3.5.7, and 3.4.0 before 3.4.6. The OpenSSL FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected because the QUIC stack is outside the FIPS module boundary.
Are you exposed to this one?
Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.
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.
Mitigation
If you can’t patch tonight, do this now.
Remediation
Patch, then assume compromise.
Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
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.
Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
23 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
An OpenSSL vulnerability addressed in Alpine Linux 3.22.5 and 3.23.5 as part of the June 9, 2026 OpenSSL advisory.
An OpenSSL vulnerability addressed in Alpine Linux 3.24.1 as part of the June 9, 2026 advisory.
An OpenSSL QUIC stack denial-of-service vulnerability caused by unbounded memory allocation in response to repeated PATH_CHALLENGE frames, allowing remote memory exhaustion and server crash.
A moderate OpenSSL QUIC denial-of-service vulnerability where a malicious peer can trigger unbounded memory growth by flooding PATH_CHALLENGE frames, exhausting heap memory.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.