Vulnerability from bitnami_vulndb
Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the RADOS Gateway (RGW) protects STS session tokens with an AES-128-CBC handler that provides no message authentication, allowing an attacker who holds any valid STS token to tamper with it undetected and escalate to full RGW administrative access. Because the ciphertext is unauthenticated, the attacker can perform a CBC bit-flip on the acct_type, perm_type, and is_admin fields of their own token, and a forged is_admin value triggers a global administrative override that bypasses all capability checks. The attack is reachable remotely over the RGW S3 endpoint and is a self-contained modification of a token the attacker already possesses, requiring no encryption oracle and no network observation. It requires only a single valid STS token, which need not carry any elevated privileges, with STS enabled. This issue is fixed in versions 20.2.4 and 19.2.6.
{
"affected": [
{
"package": {
"ecosystem": "Bitnami",
"name": "ceph",
"purl": "pkg:bitnami/ceph"
},
"ranges": [
{
"events": [
{
"introduced": "19.0.0"
},
{
"fixed": "19.2.6"
},
{
"introduced": "20.0.0"
},
{
"fixed": "20.2.4"
}
],
"type": "SEMVER"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
],
"aliases": [
"CVE-2026-39944"
],
"database_specific": {
"cpes": [
"cpe:2.3:a:linuxfoundation:ceph:*:*:*:*:*:*:*:*"
],
"severity": "High"
},
"details": "Ceph is an open-source distributed storage platform providing object, block, and file storage. In versions prior to 20.2.4 and 19.2.6, the RADOS Gateway (RGW) protects STS session tokens with an AES-128-CBC handler that provides no message authentication, allowing an attacker who holds any valid STS token to tamper with it undetected and escalate to full RGW administrative access. Because the ciphertext is unauthenticated, the attacker can perform a CBC bit-flip on the acct_type, perm_type, and is_admin fields of their own token, and a forged is_admin value triggers a global administrative override that bypasses all capability checks. The attack is reachable remotely over the RGW S3 endpoint and is a self-contained modification of a token the attacker already possesses, requiring no encryption oracle and no network observation. It requires only a single valid STS token, which need not carry any elevated privileges, with STS enabled. This issue is fixed in versions 20.2.4 and 19.2.6.",
"id": "BIT-ceph-2026-39944",
"modified": "2026-09-02T15:04:30.450Z",
"published": "2026-09-02T14:37:33.267Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/ceph/ceph/releases/tag/v19.2.6"
},
{
"type": "WEB",
"url": "https://github.com/ceph/ceph/releases/tag/v20.2.4"
},
{
"type": "WEB",
"url": "https://github.com/ceph/ceph/security/advisories/GHSA-j73r-qrgx-jvq2"
},
{
"type": "WEB",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-39944"
}
],
"schema_version": "1.6.2",
"summary": "Ceph: CephX AES Authentication error"
}
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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.