In Modem, there is a possible out of bounds write due to an incorrect bounds check.
Affects the Modem component on listed MediaTek chipsets, including MT2716, MT2735, MT2737, MT6739 and MT6761. CVSS scores it 7.5 (high). No fix is listed.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Not reported
Do first: Workaround: The checked facts describe no workaround. Ask the device maker for guidance on limiting Modem functionality until a fix is available.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 14/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
The Modem software (cellular baseband firmware) in affected devices contains a flaw that could let an attacker write data outside its intended memory area. If a device connects to a malicious rogue base station, this could allow the attacker to gain elevated privileges on the device without user interaction.
Read the original description
In Modem, there is a possible out of bounds write due to an incorrect bounds check. This could lead to remote escalation of privilege, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01876654 / MOLY01774038; Issue ID: MSV-9803.
What to do
Workaround: The checked facts describe no workaround. Ask the device maker for guidance on limiting Modem functionality until a fix is available.
Timeline
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- CVE published
- First seen by cve.now1 day
- Record last updated
Affected versions
- MediaTek, Inc. MediaTek chipset
MT2716, MT2735, MT2737, MT6739, MT6761, MT6762, MT6763, MT6765, MT6767, MT6768, MT6769, MT6771, MT6779, MT6781, MT6783, MT6785, MT6789, MT6813, MT6815, MT6833, MT6835, MT6853, MT6855, MT6858, MT6873, MT6875, MT6877, MT6878, MT6879, MT6880, and 47 more
Evidence 1
- Link
Corrections
None so far.
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Questions about CVE-2026-20546
What does this mean?
The modem has an out-of-bounds write caused by an incorrect bounds check, so it can write outside the memory area it should use (CWE-787). The advisory does not describe what an attacker could gain.Source: mediatek.com
Am I affected, and how do I check?
The advisory covers the Modem subcomponent on listed MediaTek chipsets, including MT2716, MT2735, MT2737, MT6739 and others. No affected version ranges are given, so check the chipset model of the device.Source: mediatek.com
What should I do about it?
No fixed version is listed in the checked facts, so no upgrade target can be named. Check the MediaTek advisory or your device maker for a patch.Source: mediatek.com
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What if there's no patch?
The checked facts describe no workaround. Ask the device maker for guidance on limiting Modem functionality until a fix is available.Source: mediatek.com