CVE-2026-50139 is a medium-severity race condition vulnerability in goshs.de/goshs/v2 (go), affecting versions <= 2.0.9. It is fixed in 2.1.0.
Share-link ?token=… redemption races past download limit Ecosystem: Go Package: goshs.de/goshs/v2 (github.com/patrickhener/goshs) Affected: <= v2.0.9 (every release that shipped the share-link feature) Summary ShareHandler reads the share token's DownloadLimit under RLock, releases the lock, serves the file, then re-acquires the lock to increment the counter. Concurrent requests all read the same Downloaded/DownloadLimit snapshot, all pass the check, and all are served, exceeding the operator's intended cap. Details httpserver/handler.go:968-1018: Between line 978 (RUnlock) and line 1008 (Lock), any number of goroutines can interleave and each observes the same pre-increment limit. Proof of concept Reproduced 5/5 times in a row on a 2026-era M-series Mac during verification. Impact A "single-use" share intended to deliver a one-shot secret can be redeemed N times by N concurrent clients. Combined with any token-leak vector (mail forwarding, browser history, intercepted link, etc.) this multiplies the exfiltration window. Suggested fix Reserve under the write lock before serving, refund only if the serve fails: Add a regression test that races two requests against a limit=1 token and asserts exactly one 200. Reporter: Nishant Verma. Reproduced against goshs v2.0.9 (commit 8fc1e91) on 2026-05-27.
Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing. Typical impact: TOCTOU exploits, data corruption, or privilege escalation.
CVE-2026-50139 has a CVSS score of 5.9 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (2.1.0). Upgrading removes the vulnerable code path.
go
goshs.de/goshs/v2 (<= 2.0.9)goshs.de/goshs/v2 → 2.1.0 (go)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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Already deployed Kodem? See CVE-2026-50139 in your environment →Upgrade goshs.de/goshs/v2 to 2.1.0 or later to resolve this vulnerability.
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CVE-2026-50139 is a medium-severity race condition vulnerability in goshs.de/goshs/v2 (go), affecting versions <= 2.0.9. It is fixed in 2.1.0. Multiple concurrent operations access a shared resource without proper synchronization, producing unpredictable results depending on timing.
CVE-2026-50139 has a CVSS score of 5.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
goshs.de/goshs/v2 (go) versions <= 2.0.9 is affected.
Yes. CVE-2026-50139 is fixed in 2.1.0. Upgrade to this version or later.
Whether CVE-2026-50139 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade goshs.de/goshs/v2 to 2.1.0 or later.