VulnerabilityPublished 4 May 2026Updated 8 May 2026

CVE-2026-41647: Incusd · Incus has Nil-Pointer Dereference via S3 Bucket Import

Affects github.com/lxc/incus/v6/cmd/incusdSource GCVE Database

Authoritative record:CVE-2026-41647· Medium 6.5

Not known to be exploited · CVSS 6.5 Medium.

Data as of 27 Oct 2026, 00:07 UTC

CVSS 3.1 base score

6.5Medium

How severe the flaw is on the 0–10 CVSS scale.

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector: Network
Attack Complexity: Low
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: High: There is total loss of availability, resulting in the attacker being able to fully deny access to resources in the impacted component; this loss is either sustained (while the attacker continues to deliver the attack) or persistent (the condition persists even after the attack has completed). Alternatively, the attacker has the ability to deny some availability, but the loss of availability presents a direct, serious consequence to the impacted component (e.g., the attacker cannot disrupt existing connections, but can prevent new connections; the attacker can repeatedly exploit a vulnerability that, in each instance of a successful attack, leaks a only small amount of memory, but after repeated exploitation causes a service to become completely unavailable).

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 7 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Gogithub.com/lxc/incus/v6/cmd/incusd	Affected <=6.23.0	Fixed in–

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Description

### Summary Missing error handling could lead an authenticated Incus user to cause a daemon crash through the import of a truncated storage bucket backup file. ### Details It was found that TransferManager.UploadAllFiles iterates over tar entries but only checks for io.EOF from tr.Next(). When tr.Next() returns a non-EOF error, such as unexpected EOF from a truncated archive, the header hdr is nil and the code continues to access hdr.Name, causing a nil-pointer dereference that panics the daemon. This may allow the Incus daemon to be crashed during S3 bucket restore if a truncated or corrupted backup archive is provided. A panic can occur when a malformed archive produces a non-EOF tar read error after the first entry. Any caller of UploadAllFiles that processes attacker-controlled archive content may be affected. Affected File: [https://github.com/lxc/incus/blob/v6.22.0/…server/storage/s3/transfer_manager.go#L127](https://github.com/lxc/incus/blob/v6.22.0/internal/server/storage/s3/transfer_manager.go#L127) The tar-iteration loop only checks for EOF: Affected Code: ``` for { hdr, err := tr.Next() if err == io.EOF { break // End of archive. } // Skip index.yaml file if hdr.Name == "backup/index.yaml" { ``` When tr.Next() returns a non-EOF error, hdr is nil. The code does not check for this case and immediately dereferences hdr.Name. This was confirmed as follows: Command: ``` go test ./test/fuzz -run='FuzzS3BucketUploadTarParsing/s3_nil_deref_truncated_tar' -count=1 -v ``` Output: ``` === RUN FuzzS3BucketUploadTarParsing === RUN FuzzS3BucketUploadTarParsing/s3_nil_deref_truncated_tar s3_bucket_upload_fuzz_test.go:82: UploadAllFiles panicked: runtime error: invalid memory address or nil pointer dereference --- FAIL: FuzzS3BucketUploadTarParsing/s3_nil_deref_truncated_tar (0.00s) FAIL ``` It is recommended to add a non-EOF error check after tr.Next(). Proposed Fix: ``` hdr, err := tr.Next() if err == io.EOF { break } if err != nil { return fmt.Errorf("Error reading backup archive: %w", err) } ``` A patch is available at https://github.com/lxc/incus/releases/tag/v7.0.0. ### Credits This issue was discovered and reported by the team at 7asecurity (https://7asecurity.com/)

CWE-476NULL Pointer Dereference (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #13OWASP Top 10 A10:2025: Mishandling of Exceptional Conditions (opens in a new tab)
The product dereferences a pointer that it expects to be valid but is NULL.
Implementation
For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
Requirements
Select a programming language that is not susceptible to these issues.
Implementation
Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
OWASP Cheat Sheets
Logging (opens in a new tab)
Error Handling (opens in a new tab)
OWASP ASVS 4.0.3
V11.1.7 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

WeaknessesCWE-476

Technical details

References

Community reviews

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