CVE-2022-39248 matrix-android-sdk2 vulnerable to Olm/Megolm protocol confusion
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2022-39248?
CVE-2022-39248 is a high-severity vulnerability in matrix-org matrix-android-sdk2, published on 28 Sep 2022.
Official description
matrix-android-sdk2 is the Matrix SDK for Android. Prior to version 1.5.1, an attacker cooperating with a malicious homeserver can construct messages that legitimately appear to have come from another person, without any indication such as a grey shield. Additionally, a sophisticated attacker cooperating with a malicious homeserver could employ this vulnerability to perform a targeted attack in order to send fake to-device messages appearing to originate from another user. This can allow, for example, to inject the key backup secret during a self-verification, to make a targeted device start using a malicious key backup spoofed by the homeserver. matrix-android-sdk2 would then additionally sign such a key backup with its device key, spilling trust over to other devices trusting the matrix-android-sdk2 device. These attacks are possible due to a protocol confusion vulnerability that accepts to-device messages encrypted with Megolm instead of Olm. matrix-android-sdk2 version 1.5.1 has been modified to only accept Olm-encrypted to-device messages and to stop signing backups on a successful decryption. Out of caution, several other checks have been audited or added. This attack requires coordination between a malicious home server and an attacker, so those who trust their home servers do not need a workaround.
Which versions are affected by CVE-2022-39248?
2 open source packages ship an affected version, including org.matrix.android:matrix-android-sdk2. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
org.matrix.android:matrix-android-sdk2 Maven | All versions | 1.5.1 |
org.matrix.android:matrix-android-sdk2 Maven | All versions | 1.5.1 |
Products include Matrix Software Development Kit.
How do I fix CVE-2022-39248?
Upgrade org.matrix.android:matrix-android-sdk2 to 1.5.1 or later.
Is CVE-2022-39248 being exploited?
There is no known exploitation of CVE-2022-39248 in the wild and no public exploit code.
Other vulnerabilities in matrix-org matrix-android-sdk2
Sources
Also known as GHSA-fpgf-pjjv-2qgm.