GHSA-273H-GVWR-C3QJ
Vulnerability from github – Published: 2026-05-27 19:57 – Updated: 2026-05-27 19:57The LAPI router uses gin-contrib/gzip with DefaultDecompressHandle globally (pkg/apiserver/controllers/controller.go).
This middleware decompresses incoming request bodies without enforcing a maximum decompressed size.
The endpoints /v1/watchers or /v1/watchers/login require no authentication.
An attacker can send small gzip-compressed JSON payloads that, when decompressed, result in hundreds of MB of valid JSON occupying server memory.
Sending enough requests concurrently will cause LAPI to allocate excessive heap memory, leading the OS to forcibly terminate the process.
This vulnerability is not exploitable from the network in default configurations, as LAPI only listens on the loopback interface. If developers' applications are using a multi-server setup, LAPI will be exposed in the network, in which case they are at risk if untrusted IPs can access it.
Impact
Exploiting this vulnerability will make LAPI unreachable, meaning that bouncers will not be able to fetch new decisions (but existing decisions will still be enforced) and log processors will not be able to send alerts, effectively denying the creation of new decisions.
Workarounds
If the LAPI is exposed on the network (either directly or through a reverse proxy), for example in the case of a multi-server deployment, restrict access to trusted IP addresses.
{
"affected": [
{
"package": {
"ecosystem": "Go",
"name": "github.com/crowdsecurity/crowdsec"
},
"ranges": [
{
"events": [
{
"introduced": "1.7.0"
},
{
"fixed": "1.7.8"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-44981"
],
"database_specific": {
"cwe_ids": [
"CWE-409"
],
"github_reviewed": true,
"github_reviewed_at": "2026-05-27T19:57:28Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "The LAPI router uses `gin-contrib/gzip` with `DefaultDecompressHandle` globally (`pkg/apiserver/controllers/controller.go`).\nThis middleware decompresses incoming request bodies without enforcing a maximum decompressed size. \n\nThe endpoints `/v1/watchers` or `/v1/watchers/login` require no authentication.\nAn attacker can send small gzip-compressed JSON payloads that, when decompressed, result in hundreds of MB of valid JSON occupying server memory.\nSending enough requests concurrently will cause LAPI to allocate excessive heap memory, leading the OS to forcibly terminate the process.\n \nThis vulnerability is not exploitable from the network in default configurations, as LAPI only listens on the loopback interface.\nIf developers\u0027 applications are using a multi-server setup, LAPI will be exposed in the network, in which case they are at risk if untrusted IPs can access it.\n \n### Impact\n\nExploiting this vulnerability will make LAPI unreachable, meaning that bouncers will not be able to fetch new decisions (but existing decisions will still be enforced) and log processors will not be able to send alerts, effectively denying the creation of new decisions.\n\n### Workarounds\n\nIf the LAPI is exposed on the network (either directly or through a reverse proxy), for example in the case of a multi-server deployment, restrict access to trusted IP addresses.",
"id": "GHSA-273h-gvwr-c3qj",
"modified": "2026-05-27T19:57:28Z",
"published": "2026-05-27T19:57:28Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/crowdsecurity/crowdsec/security/advisories/GHSA-273h-gvwr-c3qj"
},
{
"type": "PACKAGE",
"url": "https://github.com/crowdsecurity/crowdsec"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U",
"type": "CVSS_V4"
}
],
"summary": "CrowdSec LAPI: Denial of Service via Unbounded Gzip Decompression"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.